Related
There are many conflicting statements around. What is the best way to get the row count using PDO in PHP? Before using PDO, I just simply used mysql_num_rows.
fetchAll is something I won't want because I may sometimes be dealing with large datasets, so not good for my use.
Do you have any suggestions?
$sql = "SELECT count(*) FROM `table` WHERE foo = ?";
$result = $con->prepare($sql);
$result->execute([$bar]);
$number_of_rows = $result->fetchColumn();
Not the most elegant way to do it, plus it involves an extra query.
PDO has PDOStatement::rowCount(), which apparently does not work in MySql. What a pain.
From the PDO Doc:
For most databases,
PDOStatement::rowCount() does not
return the number of rows affected by
a SELECT statement. Instead, use
PDO::query() to issue a SELECT
COUNT(*) statement with the same
predicates as your intended SELECT
statement, then use
PDOStatement::fetchColumn() to
retrieve the number of rows that will
be returned. Your application can then
perform the correct action.
EDIT: The above code example uses a prepared statement, which is in many cases is probably unnecessary for the purpose of counting rows, so:
$nRows = $pdo->query('select count(*) from blah')->fetchColumn();
echo $nRows;
As I wrote previously in an answer to a similar question, the only reason mysql_num_rows() worked is because it was internally fetching all the rows to give you that information, even if it didn't seem like it to you.
So in PDO, your options are:
Use PDO's fetchAll() function to fetch all the rows into an array, then use count() on it.
Do an extra query to SELECT COUNT(*), as karim79 suggested.
Use MySQL's FOUND_ROWS() function UNLESS the query had SQL_CALC_FOUND_ROWS or a LIMIT clause (in which case the number of rows that were returned by the query and the number returned by FOUND_ROWS() may differ). However, this function is deprecated and will be removed in the future.
As it often happens, this question is confusing as hell. People are coming here having two different tasks in mind:
They need to know how many rows in the table
They need to know whether a query returned any rows
That's two absolutely different tasks that have nothing in common and cannot be solved by the same function. Ironically, for neither of them the actual PDOStatement::rowCount() function has to be used.
Let's see why
Counting rows in the table
Before using PDO I just simply used mysql_num_rows().
Means you already did it wrong. Using mysql_num_rows() or rowCount() to count the number of rows in the table is a real disaster in terms of consuming the server resources. A database has to read all the rows from the disk, consume the memory on the database server, then send all this heap of data to PHP, consuming PHP process' memory as well, burdening your server with absolute no reason.
Besides, selecting rows only to count them simply makes no sense. A count(*) query has to be run instead. The database will count the records out of the index, without reading the actual rows and then only one row returned.
For this purpose the code suggested in the accepted answer is fair, save for the fact it won't be an "extra" query but the only query to run.
Counting the number rows returned.
The second use case is not as disastrous as rather pointless: in case you need to know whether your query returned any data, you always have the data itself!
Say, if you are selecting only one row. All right, you can use the fetched row as a flag:
$stmt->execute();
$row = $stmt->fetch();
if (!$row) { // here! as simple as that
echo 'No data found';
}
In case you need to get many rows, then you can use fetchAll().
fetchAll() is something I won't want as I may sometimes be dealing with large datasets
Yes of course, for the first use case it would be twice as bad. But as we learned already, just don't select the rows only to count them, neither with rowCount() nor fetchAll().
But in case you are going to actually use the rows selected, there is nothing wrong in using fetchAll(). Remember that in a web application you should never select a huge amount of rows. Only rows that will be actually used on a web page should be selected, hence you've got to use LIMIT, WHERE or a similar clause in your SQL. And for such a moderate amount of data it's all right to use fetchAll(). And again, just use this function's result in the condition:
$stmt->execute();
$data = $stmt->fetchAll();
if (!$data) { // again, no rowCount() is needed!
echo 'No data found';
}
And of course it will be absolute madness to run an extra query only to tell whether your other query returned any rows, as it suggested in the two top answers.
Counting the number of rows in a large resultset
In such a rare case when you need to select a real huge amount of rows (in a console application for example), you have to use an unbuffered query, in order to reduce the amount of memory used. But this is the actual case when rowCount() won't be available, thus there is no use for this function as well.
Hence, that's the only use case when you may possibly need to run an extra query, in case you'd need to know a close estimate for the number of rows selected.
I ended up using this:
$result = $db->query($query)->fetchAll();
if (count($result) > 0) {
foreach ($result as $row) {
echo $row['blah'] . '<br />';
}
} else {
echo "<p>Nothing matched your query.</p>";
}
This post is old but Getting row count in php with PDO is simple
$stmt = $db->query('SELECT * FROM table');
$row_count = $stmt->rowCount();
This is super late, but I ran into the problem and I do this:
function countAll($table){
$dbh = dbConnect();
$sql = "select * from `$table`";
$stmt = $dbh->prepare($sql);
try { $stmt->execute();}
catch(PDOException $e){echo $e->getMessage();}
return $stmt->rowCount();
It's really simple, and easy. :)
This is an old post, but getting frustrated looking for alternatives. It is super unfortunate that PDO lacks this feature, especially as PHP and MySQL tend to go hand in hand.
There is an unfortunate flaw in using fetchColumn() as you can no longer use that result set (effectively) as the fetchColumn() moves the needle to the next row. So for example, if you have a result similar to
Fruit->Banana
Fruit->Apple
Fruit->Orange
If you use fetchColumn() you can find out that there are 3 fruits returned, but if you now loop through the result, you only have two columns, The price of fetchColumn() is the loss of the first column of results just to find out how many rows were returned. That leads to sloppy coding, and totally error ridden results if implemented.
So now, using fetchColumn() you have to implement and entirely new call and MySQL query just to get a fresh working result set. (which hopefully hasn't changed since your last query), I know, unlikely, but it can happen. Also, the overhead of dual queries on all row count validation. Which for this example is small, but parsing 2 million rows on a joined query, not a pleasant price to pay.
I love PHP and support everyone involved in its development as well as the community at large using PHP on a daily basis, but really hope this is addressed in future releases. This is 'really' my only complaint with PHP PDO, which otherwise is a great class.
Answering this because I trapped myself with it by now knowing this and maybe it will be useful.
Keep in mind that you cant fetch results twice. You have to save fetch result into array, get row count by count($array), and output results with foreach.
For example:
$query = "your_query_here";
$STH = $DBH->prepare($query);
$STH->execute();
$rows = $STH->fetchAll();
//all your results is in $rows array
$STH->setFetchMode(PDO::FETCH_ASSOC);
if (count($rows) > 0) {
foreach ($rows as $row) {
//output your rows
}
}
If you just want to get a count of rows (not the data) ie. using COUNT(*) in a prepared statement then all you need to do is retrieve the result and read the value:
$sql = "SELECT count(*) FROM `table` WHERE foo = bar";
$statement = $con->prepare($sql);
$statement->execute();
$count = $statement->fetch(PDO::FETCH_NUM); // Return array indexed by column number
return reset($count); // Resets array cursor and returns first value (the count)
Actually retrieving all the rows (data) to perform a simple count is a waste of resources. If the result set is large your server may choke on it.
Have a look at this link:
http://php.net/manual/en/pdostatement.rowcount.php
It is not recommended to use rowCount() in SELECT statements!
When it is matter of mysql how to count or get how many rows in a table with PHP PDO I use this
// count total number of rows
$query = "SELECT COUNT(*) as total_rows FROM sometable";
$stmt = $con->prepare($query);
// execute query
$stmt->execute();
// get total rows
$row = $stmt->fetch(PDO::FETCH_ASSOC);
$total_rows = $row['total_rows'];
credits goes to Mike # codeofaninja.com
To use variables within a query you have to use bindValue() or bindParam(). And do not concatenate the variables with " . $variable . "
$statement = "SELECT count(account_id) FROM account
WHERE email = ? AND is_email_confirmed;";
$preparedStatement = $this->postgreSqlHandler->prepare($statement);
$preparedStatement->bindValue(1, $account->getEmail());
$preparedStatement->execute();
$numberRows= $preparedStatement->fetchColumn();
GL
A quick one liner to get the first entry returned. This is nice for very basic queries.
<?php
$count = current($db->query("select count(*) from table")->fetch());
?>
Reference
I tried $count = $stmt->rowCount(); with Oracle 11.2 and it did not work.
I decided to used a for loop as show below.
$count = "";
$stmt = $conn->prepare($sql);
$stmt->execute();
echo "<table border='1'>\n";
while($row = $stmt->fetch(PDO::FETCH_OBJ)) {
$count++;
echo "<tr>\n";
foreach ($row as $item) {
echo "<td class='td2'>".($item !== null ? htmlentities($item, ENT_QUOTES):" ")."</td>\n";
} //foreach ends
}// while ends
echo "</table>\n";
//echo " no of rows : ". oci_num_rows($stmt);
//equivalent in pdo::prepare statement
echo "no.of rows :".$count;
For straight queries where I want a specific row, and want to know if it was found, I use something like:
function fetchSpecificRow(&$myRecord) {
$myRecord = array();
$myQuery = "some sql...";
$stmt = $this->prepare($myQuery);
$stmt->execute(array($parm1, $parm2, ...));
if ($myRecord = $stmt->fetch(PDO::FETCH_ASSOC)) return 0;
return $myErrNum;
}
The simplest way, it is only 2 lines,
$sql = $db->query("SELECT COUNT(*) FROM tablename WHERE statement='condition'");
echo $sql->fetchColumn();
So, the other answers have established that rowCount() shouldn't be used to count the rows of a SELECT statement. The documentation even says, that :
PDOStatement::rowCount() returns the number of rows affected by the last DELETE, INSERT, or UPDATE statement executed by the corresponding PDOStatement object.
https://web.archive.org/web/20220409162106/https://www.php.net/manual/en/pdostatement.rowcount.php
So it's okay for other queries, but not great for SELECT. Most answers suggest that you should make two queries, one to count rows, and one to get the subset of records you need. However, you could query the row count and your subset of the data in one request. This is a bit of an exercise in code golf, but could actually prove more efficient than two requests if the request time is a bit costly and these requests are made frequently.
If you're in PostgreSQL you can provide clean JSON output, like so:
WITH mytable as (VALUES(1,2,3),(4,5,6),(7,8,9),(10,11,12))
SELECT
jsonb_build_object(
'rowcount', (SELECT count(1) FROM mytable)
,'data', (
SELECT jsonb_agg(data.*)
FROM (
SELECT *
FROM mytable
WHERE column1 > 1 -- pagination offset
ORDER BY column1
LIMIT 2 -- page size
) as data
)
) jsondata
Output:
{"data": [
{
"column1": 4,
"column2": 5,
"column3": 6
},
{
"column1": 7,
"column2": 8,
"column3": 9
}
],
"rowcount": 4
}
If you're not in postgres, those functions won't be available, but you could do this:
WITH mytable as (VALUES(1,2,3),(4,5,6),(7,8,9),(10,11,12))
SELECT
(SELECT count(1) FROM mytable) as rowcount
,data.*
FROM (
SELECT *
FROM mytable as mytable(column1, column2, column3)
WHERE column1 > 1 -- pagination offset
ORDER BY column1
LIMIT 2 -- page size
) as data
but it will return the rowcount on every row, which might be a bit wasteful:
rowcount
column1
column2
column3
4
4
5
6
4
7
8
9
when you make a COUNT(*) in your mysql statement like in
$q = $db->query("SELECT COUNT(*) FROM ...");
your mysql query is already counting the number of result why counting again in php? to get the result of your mysql
$q = $db->query("SELECT COUNT(*) as counted FROM ...");
$nb = $q->fetch(PDO::FETCH_OBJ);
$nb = $nb->counted;
and $nb will contain the integer you have counted with your mysql statement
a bit long to write but fast to execute
Edit:
sorry for the wrong post but as some example show query with count in, I was suggesting using the mysql result, but if you don't use the count in sql fetchAll() is efficient, if you save the result in a variable you won't loose a line.
$data = $dbh->query("SELECT * FROM ...");
$table = $data->fetchAll(PDO::FETCH_OBJ);
count($table) will return the number of row and you can still use the result after like $row = $table[0] or using a foreach
foreach($table as $row){
print $row->id;
}
Here's a custom-made extension of the PDO class, with a helper function to retrieve the number of rows included by the last query's "WHERE" criteria.
You may need to add more 'handlers', though, depending on what commands you use. Right now it only works for queries that use "FROM " or "UPDATE ".
class PDO_V extends PDO
{
private $lastQuery = null;
public function query($query)
{
$this->lastQuery = $query;
return parent::query($query);
}
public function getLastQueryRowCount()
{
$lastQuery = $this->lastQuery;
$commandBeforeTableName = null;
if (strpos($lastQuery, 'FROM') !== false)
$commandBeforeTableName = 'FROM';
if (strpos($lastQuery, 'UPDATE') !== false)
$commandBeforeTableName = 'UPDATE';
$after = substr($lastQuery, strpos($lastQuery, $commandBeforeTableName) + (strlen($commandBeforeTableName) + 1));
$table = substr($after, 0, strpos($after, ' '));
$wherePart = substr($lastQuery, strpos($lastQuery, 'WHERE'));
$result = parent::query("SELECT COUNT(*) FROM $table " . $wherePart);
if ($result == null)
return 0;
return $result->fetchColumn();
}
}
You can combine the best method into one line or function, and have the new query auto-generated for you:
function getRowCount($q){
global $db;
return $db->query(preg_replace('/SELECT [A-Za-z,]+ FROM /i','SELECT count(*) FROM ',$q))->fetchColumn();
}
$numRows = getRowCount($query);
There is a simple solution. If you use PDO connect to your DB like this:
try {
$handler = new PDO('mysql:host=localhost;dbname=name_of_your_db', 'your_login', 'your_password');
$handler -> setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
} catch (PDOException $e) {
echo $e->getMessage();
}
Now, if you want to know how many rows are existing in your table and you have for example column 'id' as the primary key, the query to DB will be:
$query = $handler->query("SELECT id FROM your_table_name");
And finally, to get the amount of the rows matching your query, write like this:
$amountOfRows = $query->rowCount();
Or you can write:
$query = $handler ->query("SELECT COUNT(id) FROM your_table_name");
$amountOfRows = $query->rowCount();
Or, if you want to know how many products there are in the table 'products' have the price between 10 and 20, write this query:
$query = $handler ->query("SELECT id FROM products WHERE price BETWEEN 10 AND
20");
$amountOfRows = $query->rowCount();
There are many conflicting statements around. What is the best way to get the row count using PDO in PHP? Before using PDO, I just simply used mysql_num_rows.
fetchAll is something I won't want because I may sometimes be dealing with large datasets, so not good for my use.
Do you have any suggestions?
$sql = "SELECT count(*) FROM `table` WHERE foo = ?";
$result = $con->prepare($sql);
$result->execute([$bar]);
$number_of_rows = $result->fetchColumn();
Not the most elegant way to do it, plus it involves an extra query.
PDO has PDOStatement::rowCount(), which apparently does not work in MySql. What a pain.
From the PDO Doc:
For most databases,
PDOStatement::rowCount() does not
return the number of rows affected by
a SELECT statement. Instead, use
PDO::query() to issue a SELECT
COUNT(*) statement with the same
predicates as your intended SELECT
statement, then use
PDOStatement::fetchColumn() to
retrieve the number of rows that will
be returned. Your application can then
perform the correct action.
EDIT: The above code example uses a prepared statement, which is in many cases is probably unnecessary for the purpose of counting rows, so:
$nRows = $pdo->query('select count(*) from blah')->fetchColumn();
echo $nRows;
As I wrote previously in an answer to a similar question, the only reason mysql_num_rows() worked is because it was internally fetching all the rows to give you that information, even if it didn't seem like it to you.
So in PDO, your options are:
Use PDO's fetchAll() function to fetch all the rows into an array, then use count() on it.
Do an extra query to SELECT COUNT(*), as karim79 suggested.
Use MySQL's FOUND_ROWS() function UNLESS the query had SQL_CALC_FOUND_ROWS or a LIMIT clause (in which case the number of rows that were returned by the query and the number returned by FOUND_ROWS() may differ). However, this function is deprecated and will be removed in the future.
As it often happens, this question is confusing as hell. People are coming here having two different tasks in mind:
They need to know how many rows in the table
They need to know whether a query returned any rows
That's two absolutely different tasks that have nothing in common and cannot be solved by the same function. Ironically, for neither of them the actual PDOStatement::rowCount() function has to be used.
Let's see why
Counting rows in the table
Before using PDO I just simply used mysql_num_rows().
Means you already did it wrong. Using mysql_num_rows() or rowCount() to count the number of rows in the table is a real disaster in terms of consuming the server resources. A database has to read all the rows from the disk, consume the memory on the database server, then send all this heap of data to PHP, consuming PHP process' memory as well, burdening your server with absolute no reason.
Besides, selecting rows only to count them simply makes no sense. A count(*) query has to be run instead. The database will count the records out of the index, without reading the actual rows and then only one row returned.
For this purpose the code suggested in the accepted answer is fair, save for the fact it won't be an "extra" query but the only query to run.
Counting the number rows returned.
The second use case is not as disastrous as rather pointless: in case you need to know whether your query returned any data, you always have the data itself!
Say, if you are selecting only one row. All right, you can use the fetched row as a flag:
$stmt->execute();
$row = $stmt->fetch();
if (!$row) { // here! as simple as that
echo 'No data found';
}
In case you need to get many rows, then you can use fetchAll().
fetchAll() is something I won't want as I may sometimes be dealing with large datasets
Yes of course, for the first use case it would be twice as bad. But as we learned already, just don't select the rows only to count them, neither with rowCount() nor fetchAll().
But in case you are going to actually use the rows selected, there is nothing wrong in using fetchAll(). Remember that in a web application you should never select a huge amount of rows. Only rows that will be actually used on a web page should be selected, hence you've got to use LIMIT, WHERE or a similar clause in your SQL. And for such a moderate amount of data it's all right to use fetchAll(). And again, just use this function's result in the condition:
$stmt->execute();
$data = $stmt->fetchAll();
if (!$data) { // again, no rowCount() is needed!
echo 'No data found';
}
And of course it will be absolute madness to run an extra query only to tell whether your other query returned any rows, as it suggested in the two top answers.
Counting the number of rows in a large resultset
In such a rare case when you need to select a real huge amount of rows (in a console application for example), you have to use an unbuffered query, in order to reduce the amount of memory used. But this is the actual case when rowCount() won't be available, thus there is no use for this function as well.
Hence, that's the only use case when you may possibly need to run an extra query, in case you'd need to know a close estimate for the number of rows selected.
I ended up using this:
$result = $db->query($query)->fetchAll();
if (count($result) > 0) {
foreach ($result as $row) {
echo $row['blah'] . '<br />';
}
} else {
echo "<p>Nothing matched your query.</p>";
}
This post is old but Getting row count in php with PDO is simple
$stmt = $db->query('SELECT * FROM table');
$row_count = $stmt->rowCount();
This is super late, but I ran into the problem and I do this:
function countAll($table){
$dbh = dbConnect();
$sql = "select * from `$table`";
$stmt = $dbh->prepare($sql);
try { $stmt->execute();}
catch(PDOException $e){echo $e->getMessage();}
return $stmt->rowCount();
It's really simple, and easy. :)
This is an old post, but getting frustrated looking for alternatives. It is super unfortunate that PDO lacks this feature, especially as PHP and MySQL tend to go hand in hand.
There is an unfortunate flaw in using fetchColumn() as you can no longer use that result set (effectively) as the fetchColumn() moves the needle to the next row. So for example, if you have a result similar to
Fruit->Banana
Fruit->Apple
Fruit->Orange
If you use fetchColumn() you can find out that there are 3 fruits returned, but if you now loop through the result, you only have two columns, The price of fetchColumn() is the loss of the first column of results just to find out how many rows were returned. That leads to sloppy coding, and totally error ridden results if implemented.
So now, using fetchColumn() you have to implement and entirely new call and MySQL query just to get a fresh working result set. (which hopefully hasn't changed since your last query), I know, unlikely, but it can happen. Also, the overhead of dual queries on all row count validation. Which for this example is small, but parsing 2 million rows on a joined query, not a pleasant price to pay.
I love PHP and support everyone involved in its development as well as the community at large using PHP on a daily basis, but really hope this is addressed in future releases. This is 'really' my only complaint with PHP PDO, which otherwise is a great class.
Answering this because I trapped myself with it by now knowing this and maybe it will be useful.
Keep in mind that you cant fetch results twice. You have to save fetch result into array, get row count by count($array), and output results with foreach.
For example:
$query = "your_query_here";
$STH = $DBH->prepare($query);
$STH->execute();
$rows = $STH->fetchAll();
//all your results is in $rows array
$STH->setFetchMode(PDO::FETCH_ASSOC);
if (count($rows) > 0) {
foreach ($rows as $row) {
//output your rows
}
}
If you just want to get a count of rows (not the data) ie. using COUNT(*) in a prepared statement then all you need to do is retrieve the result and read the value:
$sql = "SELECT count(*) FROM `table` WHERE foo = bar";
$statement = $con->prepare($sql);
$statement->execute();
$count = $statement->fetch(PDO::FETCH_NUM); // Return array indexed by column number
return reset($count); // Resets array cursor and returns first value (the count)
Actually retrieving all the rows (data) to perform a simple count is a waste of resources. If the result set is large your server may choke on it.
Have a look at this link:
http://php.net/manual/en/pdostatement.rowcount.php
It is not recommended to use rowCount() in SELECT statements!
When it is matter of mysql how to count or get how many rows in a table with PHP PDO I use this
// count total number of rows
$query = "SELECT COUNT(*) as total_rows FROM sometable";
$stmt = $con->prepare($query);
// execute query
$stmt->execute();
// get total rows
$row = $stmt->fetch(PDO::FETCH_ASSOC);
$total_rows = $row['total_rows'];
credits goes to Mike # codeofaninja.com
To use variables within a query you have to use bindValue() or bindParam(). And do not concatenate the variables with " . $variable . "
$statement = "SELECT count(account_id) FROM account
WHERE email = ? AND is_email_confirmed;";
$preparedStatement = $this->postgreSqlHandler->prepare($statement);
$preparedStatement->bindValue(1, $account->getEmail());
$preparedStatement->execute();
$numberRows= $preparedStatement->fetchColumn();
GL
A quick one liner to get the first entry returned. This is nice for very basic queries.
<?php
$count = current($db->query("select count(*) from table")->fetch());
?>
Reference
I tried $count = $stmt->rowCount(); with Oracle 11.2 and it did not work.
I decided to used a for loop as show below.
$count = "";
$stmt = $conn->prepare($sql);
$stmt->execute();
echo "<table border='1'>\n";
while($row = $stmt->fetch(PDO::FETCH_OBJ)) {
$count++;
echo "<tr>\n";
foreach ($row as $item) {
echo "<td class='td2'>".($item !== null ? htmlentities($item, ENT_QUOTES):" ")."</td>\n";
} //foreach ends
}// while ends
echo "</table>\n";
//echo " no of rows : ". oci_num_rows($stmt);
//equivalent in pdo::prepare statement
echo "no.of rows :".$count;
For straight queries where I want a specific row, and want to know if it was found, I use something like:
function fetchSpecificRow(&$myRecord) {
$myRecord = array();
$myQuery = "some sql...";
$stmt = $this->prepare($myQuery);
$stmt->execute(array($parm1, $parm2, ...));
if ($myRecord = $stmt->fetch(PDO::FETCH_ASSOC)) return 0;
return $myErrNum;
}
The simplest way, it is only 2 lines,
$sql = $db->query("SELECT COUNT(*) FROM tablename WHERE statement='condition'");
echo $sql->fetchColumn();
So, the other answers have established that rowCount() shouldn't be used to count the rows of a SELECT statement. The documentation even says, that :
PDOStatement::rowCount() returns the number of rows affected by the last DELETE, INSERT, or UPDATE statement executed by the corresponding PDOStatement object.
https://web.archive.org/web/20220409162106/https://www.php.net/manual/en/pdostatement.rowcount.php
So it's okay for other queries, but not great for SELECT. Most answers suggest that you should make two queries, one to count rows, and one to get the subset of records you need. However, you could query the row count and your subset of the data in one request. This is a bit of an exercise in code golf, but could actually prove more efficient than two requests if the request time is a bit costly and these requests are made frequently.
If you're in PostgreSQL you can provide clean JSON output, like so:
WITH mytable as (VALUES(1,2,3),(4,5,6),(7,8,9),(10,11,12))
SELECT
jsonb_build_object(
'rowcount', (SELECT count(1) FROM mytable)
,'data', (
SELECT jsonb_agg(data.*)
FROM (
SELECT *
FROM mytable
WHERE column1 > 1 -- pagination offset
ORDER BY column1
LIMIT 2 -- page size
) as data
)
) jsondata
Output:
{"data": [
{
"column1": 4,
"column2": 5,
"column3": 6
},
{
"column1": 7,
"column2": 8,
"column3": 9
}
],
"rowcount": 4
}
If you're not in postgres, those functions won't be available, but you could do this:
WITH mytable as (VALUES(1,2,3),(4,5,6),(7,8,9),(10,11,12))
SELECT
(SELECT count(1) FROM mytable) as rowcount
,data.*
FROM (
SELECT *
FROM mytable as mytable(column1, column2, column3)
WHERE column1 > 1 -- pagination offset
ORDER BY column1
LIMIT 2 -- page size
) as data
but it will return the rowcount on every row, which might be a bit wasteful:
rowcount
column1
column2
column3
4
4
5
6
4
7
8
9
when you make a COUNT(*) in your mysql statement like in
$q = $db->query("SELECT COUNT(*) FROM ...");
your mysql query is already counting the number of result why counting again in php? to get the result of your mysql
$q = $db->query("SELECT COUNT(*) as counted FROM ...");
$nb = $q->fetch(PDO::FETCH_OBJ);
$nb = $nb->counted;
and $nb will contain the integer you have counted with your mysql statement
a bit long to write but fast to execute
Edit:
sorry for the wrong post but as some example show query with count in, I was suggesting using the mysql result, but if you don't use the count in sql fetchAll() is efficient, if you save the result in a variable you won't loose a line.
$data = $dbh->query("SELECT * FROM ...");
$table = $data->fetchAll(PDO::FETCH_OBJ);
count($table) will return the number of row and you can still use the result after like $row = $table[0] or using a foreach
foreach($table as $row){
print $row->id;
}
Here's a custom-made extension of the PDO class, with a helper function to retrieve the number of rows included by the last query's "WHERE" criteria.
You may need to add more 'handlers', though, depending on what commands you use. Right now it only works for queries that use "FROM " or "UPDATE ".
class PDO_V extends PDO
{
private $lastQuery = null;
public function query($query)
{
$this->lastQuery = $query;
return parent::query($query);
}
public function getLastQueryRowCount()
{
$lastQuery = $this->lastQuery;
$commandBeforeTableName = null;
if (strpos($lastQuery, 'FROM') !== false)
$commandBeforeTableName = 'FROM';
if (strpos($lastQuery, 'UPDATE') !== false)
$commandBeforeTableName = 'UPDATE';
$after = substr($lastQuery, strpos($lastQuery, $commandBeforeTableName) + (strlen($commandBeforeTableName) + 1));
$table = substr($after, 0, strpos($after, ' '));
$wherePart = substr($lastQuery, strpos($lastQuery, 'WHERE'));
$result = parent::query("SELECT COUNT(*) FROM $table " . $wherePart);
if ($result == null)
return 0;
return $result->fetchColumn();
}
}
You can combine the best method into one line or function, and have the new query auto-generated for you:
function getRowCount($q){
global $db;
return $db->query(preg_replace('/SELECT [A-Za-z,]+ FROM /i','SELECT count(*) FROM ',$q))->fetchColumn();
}
$numRows = getRowCount($query);
There is a simple solution. If you use PDO connect to your DB like this:
try {
$handler = new PDO('mysql:host=localhost;dbname=name_of_your_db', 'your_login', 'your_password');
$handler -> setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
} catch (PDOException $e) {
echo $e->getMessage();
}
Now, if you want to know how many rows are existing in your table and you have for example column 'id' as the primary key, the query to DB will be:
$query = $handler->query("SELECT id FROM your_table_name");
And finally, to get the amount of the rows matching your query, write like this:
$amountOfRows = $query->rowCount();
Or you can write:
$query = $handler ->query("SELECT COUNT(id) FROM your_table_name");
$amountOfRows = $query->rowCount();
Or, if you want to know how many products there are in the table 'products' have the price between 10 and 20, write this query:
$query = $handler ->query("SELECT id FROM products WHERE price BETWEEN 10 AND
20");
$amountOfRows = $query->rowCount();
With mysqli I can get the number of rows from a select query by using mysqli_num_rows. I can't find a way to do that with PDO without having to do a separate query like SELECT COUNT(*)? I don't see the point in doing a separate query when I already have a recordset.
You could use SQL_CALC_FOUND_ROWS as documented here. For example:
$result = $db->prepare("SELECT SQL_CALC_FOUND_ROWS id, name FROM fruit WHERE calories > 100");
$result->execute();
$result = $db->prepare("SELECT FOUND_ROWS()");
$result->execute();
$row_count =$result->fetchColumn();
echo $row_count;
This option is normally used to get full match counts when you have a LIMIT clause, however, it works just fine without one, and it's much more efficient than issuing the same query again with a COUNT(*) since it just retrieves the count value stored by the first query value and does not have to run another full query.
In Pdo you use rowCount. Example: $string-> rowCount ();
RTM: http://php.net/manual/en/pdostatement.rowcount.php
For most databases, PDOStatement::rowCount() does not return the
number of rows affected by a SELECT statement. Instead, use
PDO::query() to issue a SELECT COUNT(*) statement with the same
predicates as your intended SELECT statement, then use
PDOStatement::fetchColumn() to retrieve the number of rows that will
be returned. Your application can then perform the correct action.
$sql = "SELECT COUNT(*) FROM fruit WHERE calories > 100";
if ($res = $conn->query($sql)) {
/* Check the number of rows that match the SELECT statement */
if ($res->fetchColumn() > 0) {
/* .... */
I don't want to copy the whole PHP.net page, please just read it.
Why does PDO not have num_rows ?
You may think it's slower to have 2 queries but it isn't. PDO is a general client library for several database systems, not only MySQL. For performance reasons, not everys database system has internal, technical ability to calculate the total rows in select uppon the query. Knowing the total number of rows requires to examine all rows before serving them.
try this:
$sql = "SELECT count(id) FROM `table` WHERE condition";
$result = $db->prepare($sql);
$result->execute();
$row_count =$result->fetchColumn();
echo $row_count;
There are many conflicting statements around. What is the best way to get the row count using PDO in PHP? Before using PDO, I just simply used mysql_num_rows.
fetchAll is something I won't want because I may sometimes be dealing with large datasets, so not good for my use.
Do you have any suggestions?
$sql = "SELECT count(*) FROM `table` WHERE foo = ?";
$result = $con->prepare($sql);
$result->execute([$bar]);
$number_of_rows = $result->fetchColumn();
Not the most elegant way to do it, plus it involves an extra query.
PDO has PDOStatement::rowCount(), which apparently does not work in MySql. What a pain.
From the PDO Doc:
For most databases,
PDOStatement::rowCount() does not
return the number of rows affected by
a SELECT statement. Instead, use
PDO::query() to issue a SELECT
COUNT(*) statement with the same
predicates as your intended SELECT
statement, then use
PDOStatement::fetchColumn() to
retrieve the number of rows that will
be returned. Your application can then
perform the correct action.
EDIT: The above code example uses a prepared statement, which is in many cases is probably unnecessary for the purpose of counting rows, so:
$nRows = $pdo->query('select count(*) from blah')->fetchColumn();
echo $nRows;
As I wrote previously in an answer to a similar question, the only reason mysql_num_rows() worked is because it was internally fetching all the rows to give you that information, even if it didn't seem like it to you.
So in PDO, your options are:
Use PDO's fetchAll() function to fetch all the rows into an array, then use count() on it.
Do an extra query to SELECT COUNT(*), as karim79 suggested.
Use MySQL's FOUND_ROWS() function UNLESS the query had SQL_CALC_FOUND_ROWS or a LIMIT clause (in which case the number of rows that were returned by the query and the number returned by FOUND_ROWS() may differ). However, this function is deprecated and will be removed in the future.
As it often happens, this question is confusing as hell. People are coming here having two different tasks in mind:
They need to know how many rows in the table
They need to know whether a query returned any rows
That's two absolutely different tasks that have nothing in common and cannot be solved by the same function. Ironically, for neither of them the actual PDOStatement::rowCount() function has to be used.
Let's see why
Counting rows in the table
Before using PDO I just simply used mysql_num_rows().
Means you already did it wrong. Using mysql_num_rows() or rowCount() to count the number of rows in the table is a real disaster in terms of consuming the server resources. A database has to read all the rows from the disk, consume the memory on the database server, then send all this heap of data to PHP, consuming PHP process' memory as well, burdening your server with absolute no reason.
Besides, selecting rows only to count them simply makes no sense. A count(*) query has to be run instead. The database will count the records out of the index, without reading the actual rows and then only one row returned.
For this purpose the code suggested in the accepted answer is fair, save for the fact it won't be an "extra" query but the only query to run.
Counting the number rows returned.
The second use case is not as disastrous as rather pointless: in case you need to know whether your query returned any data, you always have the data itself!
Say, if you are selecting only one row. All right, you can use the fetched row as a flag:
$stmt->execute();
$row = $stmt->fetch();
if (!$row) { // here! as simple as that
echo 'No data found';
}
In case you need to get many rows, then you can use fetchAll().
fetchAll() is something I won't want as I may sometimes be dealing with large datasets
Yes of course, for the first use case it would be twice as bad. But as we learned already, just don't select the rows only to count them, neither with rowCount() nor fetchAll().
But in case you are going to actually use the rows selected, there is nothing wrong in using fetchAll(). Remember that in a web application you should never select a huge amount of rows. Only rows that will be actually used on a web page should be selected, hence you've got to use LIMIT, WHERE or a similar clause in your SQL. And for such a moderate amount of data it's all right to use fetchAll(). And again, just use this function's result in the condition:
$stmt->execute();
$data = $stmt->fetchAll();
if (!$data) { // again, no rowCount() is needed!
echo 'No data found';
}
And of course it will be absolute madness to run an extra query only to tell whether your other query returned any rows, as it suggested in the two top answers.
Counting the number of rows in a large resultset
In such a rare case when you need to select a real huge amount of rows (in a console application for example), you have to use an unbuffered query, in order to reduce the amount of memory used. But this is the actual case when rowCount() won't be available, thus there is no use for this function as well.
Hence, that's the only use case when you may possibly need to run an extra query, in case you'd need to know a close estimate for the number of rows selected.
I ended up using this:
$result = $db->query($query)->fetchAll();
if (count($result) > 0) {
foreach ($result as $row) {
echo $row['blah'] . '<br />';
}
} else {
echo "<p>Nothing matched your query.</p>";
}
This post is old but Getting row count in php with PDO is simple
$stmt = $db->query('SELECT * FROM table');
$row_count = $stmt->rowCount();
This is super late, but I ran into the problem and I do this:
function countAll($table){
$dbh = dbConnect();
$sql = "select * from `$table`";
$stmt = $dbh->prepare($sql);
try { $stmt->execute();}
catch(PDOException $e){echo $e->getMessage();}
return $stmt->rowCount();
It's really simple, and easy. :)
This is an old post, but getting frustrated looking for alternatives. It is super unfortunate that PDO lacks this feature, especially as PHP and MySQL tend to go hand in hand.
There is an unfortunate flaw in using fetchColumn() as you can no longer use that result set (effectively) as the fetchColumn() moves the needle to the next row. So for example, if you have a result similar to
Fruit->Banana
Fruit->Apple
Fruit->Orange
If you use fetchColumn() you can find out that there are 3 fruits returned, but if you now loop through the result, you only have two columns, The price of fetchColumn() is the loss of the first column of results just to find out how many rows were returned. That leads to sloppy coding, and totally error ridden results if implemented.
So now, using fetchColumn() you have to implement and entirely new call and MySQL query just to get a fresh working result set. (which hopefully hasn't changed since your last query), I know, unlikely, but it can happen. Also, the overhead of dual queries on all row count validation. Which for this example is small, but parsing 2 million rows on a joined query, not a pleasant price to pay.
I love PHP and support everyone involved in its development as well as the community at large using PHP on a daily basis, but really hope this is addressed in future releases. This is 'really' my only complaint with PHP PDO, which otherwise is a great class.
Answering this because I trapped myself with it by now knowing this and maybe it will be useful.
Keep in mind that you cant fetch results twice. You have to save fetch result into array, get row count by count($array), and output results with foreach.
For example:
$query = "your_query_here";
$STH = $DBH->prepare($query);
$STH->execute();
$rows = $STH->fetchAll();
//all your results is in $rows array
$STH->setFetchMode(PDO::FETCH_ASSOC);
if (count($rows) > 0) {
foreach ($rows as $row) {
//output your rows
}
}
If you just want to get a count of rows (not the data) ie. using COUNT(*) in a prepared statement then all you need to do is retrieve the result and read the value:
$sql = "SELECT count(*) FROM `table` WHERE foo = bar";
$statement = $con->prepare($sql);
$statement->execute();
$count = $statement->fetch(PDO::FETCH_NUM); // Return array indexed by column number
return reset($count); // Resets array cursor and returns first value (the count)
Actually retrieving all the rows (data) to perform a simple count is a waste of resources. If the result set is large your server may choke on it.
Have a look at this link:
http://php.net/manual/en/pdostatement.rowcount.php
It is not recommended to use rowCount() in SELECT statements!
When it is matter of mysql how to count or get how many rows in a table with PHP PDO I use this
// count total number of rows
$query = "SELECT COUNT(*) as total_rows FROM sometable";
$stmt = $con->prepare($query);
// execute query
$stmt->execute();
// get total rows
$row = $stmt->fetch(PDO::FETCH_ASSOC);
$total_rows = $row['total_rows'];
credits goes to Mike # codeofaninja.com
To use variables within a query you have to use bindValue() or bindParam(). And do not concatenate the variables with " . $variable . "
$statement = "SELECT count(account_id) FROM account
WHERE email = ? AND is_email_confirmed;";
$preparedStatement = $this->postgreSqlHandler->prepare($statement);
$preparedStatement->bindValue(1, $account->getEmail());
$preparedStatement->execute();
$numberRows= $preparedStatement->fetchColumn();
GL
A quick one liner to get the first entry returned. This is nice for very basic queries.
<?php
$count = current($db->query("select count(*) from table")->fetch());
?>
Reference
I tried $count = $stmt->rowCount(); with Oracle 11.2 and it did not work.
I decided to used a for loop as show below.
$count = "";
$stmt = $conn->prepare($sql);
$stmt->execute();
echo "<table border='1'>\n";
while($row = $stmt->fetch(PDO::FETCH_OBJ)) {
$count++;
echo "<tr>\n";
foreach ($row as $item) {
echo "<td class='td2'>".($item !== null ? htmlentities($item, ENT_QUOTES):" ")."</td>\n";
} //foreach ends
}// while ends
echo "</table>\n";
//echo " no of rows : ". oci_num_rows($stmt);
//equivalent in pdo::prepare statement
echo "no.of rows :".$count;
For straight queries where I want a specific row, and want to know if it was found, I use something like:
function fetchSpecificRow(&$myRecord) {
$myRecord = array();
$myQuery = "some sql...";
$stmt = $this->prepare($myQuery);
$stmt->execute(array($parm1, $parm2, ...));
if ($myRecord = $stmt->fetch(PDO::FETCH_ASSOC)) return 0;
return $myErrNum;
}
The simplest way, it is only 2 lines,
$sql = $db->query("SELECT COUNT(*) FROM tablename WHERE statement='condition'");
echo $sql->fetchColumn();
So, the other answers have established that rowCount() shouldn't be used to count the rows of a SELECT statement. The documentation even says, that :
PDOStatement::rowCount() returns the number of rows affected by the last DELETE, INSERT, or UPDATE statement executed by the corresponding PDOStatement object.
https://web.archive.org/web/20220409162106/https://www.php.net/manual/en/pdostatement.rowcount.php
So it's okay for other queries, but not great for SELECT. Most answers suggest that you should make two queries, one to count rows, and one to get the subset of records you need. However, you could query the row count and your subset of the data in one request. This is a bit of an exercise in code golf, but could actually prove more efficient than two requests if the request time is a bit costly and these requests are made frequently.
If you're in PostgreSQL you can provide clean JSON output, like so:
WITH mytable as (VALUES(1,2,3),(4,5,6),(7,8,9),(10,11,12))
SELECT
jsonb_build_object(
'rowcount', (SELECT count(1) FROM mytable)
,'data', (
SELECT jsonb_agg(data.*)
FROM (
SELECT *
FROM mytable
WHERE column1 > 1 -- pagination offset
ORDER BY column1
LIMIT 2 -- page size
) as data
)
) jsondata
Output:
{"data": [
{
"column1": 4,
"column2": 5,
"column3": 6
},
{
"column1": 7,
"column2": 8,
"column3": 9
}
],
"rowcount": 4
}
If you're not in postgres, those functions won't be available, but you could do this:
WITH mytable as (VALUES(1,2,3),(4,5,6),(7,8,9),(10,11,12))
SELECT
(SELECT count(1) FROM mytable) as rowcount
,data.*
FROM (
SELECT *
FROM mytable as mytable(column1, column2, column3)
WHERE column1 > 1 -- pagination offset
ORDER BY column1
LIMIT 2 -- page size
) as data
but it will return the rowcount on every row, which might be a bit wasteful:
rowcount
column1
column2
column3
4
4
5
6
4
7
8
9
when you make a COUNT(*) in your mysql statement like in
$q = $db->query("SELECT COUNT(*) FROM ...");
your mysql query is already counting the number of result why counting again in php? to get the result of your mysql
$q = $db->query("SELECT COUNT(*) as counted FROM ...");
$nb = $q->fetch(PDO::FETCH_OBJ);
$nb = $nb->counted;
and $nb will contain the integer you have counted with your mysql statement
a bit long to write but fast to execute
Edit:
sorry for the wrong post but as some example show query with count in, I was suggesting using the mysql result, but if you don't use the count in sql fetchAll() is efficient, if you save the result in a variable you won't loose a line.
$data = $dbh->query("SELECT * FROM ...");
$table = $data->fetchAll(PDO::FETCH_OBJ);
count($table) will return the number of row and you can still use the result after like $row = $table[0] or using a foreach
foreach($table as $row){
print $row->id;
}
Here's a custom-made extension of the PDO class, with a helper function to retrieve the number of rows included by the last query's "WHERE" criteria.
You may need to add more 'handlers', though, depending on what commands you use. Right now it only works for queries that use "FROM " or "UPDATE ".
class PDO_V extends PDO
{
private $lastQuery = null;
public function query($query)
{
$this->lastQuery = $query;
return parent::query($query);
}
public function getLastQueryRowCount()
{
$lastQuery = $this->lastQuery;
$commandBeforeTableName = null;
if (strpos($lastQuery, 'FROM') !== false)
$commandBeforeTableName = 'FROM';
if (strpos($lastQuery, 'UPDATE') !== false)
$commandBeforeTableName = 'UPDATE';
$after = substr($lastQuery, strpos($lastQuery, $commandBeforeTableName) + (strlen($commandBeforeTableName) + 1));
$table = substr($after, 0, strpos($after, ' '));
$wherePart = substr($lastQuery, strpos($lastQuery, 'WHERE'));
$result = parent::query("SELECT COUNT(*) FROM $table " . $wherePart);
if ($result == null)
return 0;
return $result->fetchColumn();
}
}
You can combine the best method into one line or function, and have the new query auto-generated for you:
function getRowCount($q){
global $db;
return $db->query(preg_replace('/SELECT [A-Za-z,]+ FROM /i','SELECT count(*) FROM ',$q))->fetchColumn();
}
$numRows = getRowCount($query);
There is a simple solution. If you use PDO connect to your DB like this:
try {
$handler = new PDO('mysql:host=localhost;dbname=name_of_your_db', 'your_login', 'your_password');
$handler -> setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
} catch (PDOException $e) {
echo $e->getMessage();
}
Now, if you want to know how many rows are existing in your table and you have for example column 'id' as the primary key, the query to DB will be:
$query = $handler->query("SELECT id FROM your_table_name");
And finally, to get the amount of the rows matching your query, write like this:
$amountOfRows = $query->rowCount();
Or you can write:
$query = $handler ->query("SELECT COUNT(id) FROM your_table_name");
$amountOfRows = $query->rowCount();
Or, if you want to know how many products there are in the table 'products' have the price between 10 and 20, write this query:
$query = $handler ->query("SELECT id FROM products WHERE price BETWEEN 10 AND
20");
$amountOfRows = $query->rowCount();
How can I count the number of rows that a MySQL query returned?
Getting total rows in a query result...
You could just iterate the result and count them. You don't say what language or client library you are using, but the API does provide a mysql_num_rows function which can tell you the number of rows in a result.
This is exposed in PHP, for example, as the mysqli_num_rows function. As you've edited the question to mention you're using PHP, here's a simple example using mysqli functions:
$link = mysqli_connect("localhost", "user", "password", "database");
$result = mysqli_query($link, "SELECT * FROM table1");
$num_rows = mysqli_num_rows($result);
echo "$num_rows Rows\n";
Getting a count of rows matching some criteria...
Just use COUNT(*) - see Counting Rows in the MySQL manual. For example:
SELECT COUNT(*) FROM foo WHERE bar= 'value';
Get total rows when LIMIT is used...
If you'd used a LIMIT clause but want to know how many rows you'd get without it, use SQL_CALC_FOUND_ROWS in your query, followed by SELECT FOUND_ROWS();
SELECT SQL_CALC_FOUND_ROWS * FROM foo
WHERE bar="value"
LIMIT 10;
SELECT FOUND_ROWS();
For very large tables, this isn't going to be particularly efficient, and you're better off running a simpler query to obtain a count and caching it before running your queries to get pages of data.
In the event you have to solve the problem with simple SQL you might use an inline view.
select count(*) from (select * from foo) as x;
If your SQL query has a LIMIT clause and you want to know how many results total are in that data set you can use SQL_CALC_FOUND_ROWS followed by SELECT FOUND_ROWS(); This returns the number of rows A LOT more efficiently than using COUNT(*)
Example (straight from MySQL docs):
mysql> SELECT SQL_CALC_FOUND_ROWS * FROM tbl_name
-> WHERE id > 100 LIMIT 10;
mysql> SELECT FOUND_ROWS();
Use 2 queries as below, One to fetch the data with limit and other to get the no of total matched rows.
Ex:
SELECT * FROM tbl_name WHERE id > 1000 LIMIT 10;
SELECT COUNT(*) FROM tbl_name WHERE id > 1000;
As described by Mysql guide , this is the most optimized way, and also SQL_CALC_FOUND_ROWS query modifier and FOUND_ROWS() function are deprecated as of MySQL 8.0.17
SELECT SQL_CALC_FOUND_ROWS *
FROM table1
WHERE ...;
SELECT FOUND_ROWS();
FOUND_ROWS() must be called immediately after the query.
If you want the result plus the number of rows returned do something like this. Using PHP.
$query = "SELECT * FROM Employee";
$result = mysql_query($query);
echo "There are ".mysql_num_rows($result)." Employee(s).";
Assuming you're using the mysql_ or mysqli_ functions, your question should already have been answered by others.
However if you're using PDO, there is no easy function to return the number of rows retrieved by a select statement, unfortunately. You have to use count() on the resultset (after assigning it to a local variable, usually).
Or if you're only interested in the number and not the data, PDOStatement::fetchColumn() on your SELECT COUNT(1)... result.
The basics
To get the number of matching rows in SQL you would usually use COUNT(*). For example:
SELECT COUNT(*) FROM some_table
To get that in value in PHP you need to fetch the value from the first column in the first row of the returned result. An example using PDO and mysqli is demonstrated below.
However, if you want to fetch the results and then still know how many records you fetched using PHP, you could use count() or avail of the pre-populated count in the result object if your DB API offers it e.g. mysqli's num_rows.
Using MySQLi
Using mysqli you can fetch the first row using fetch_row() and then access the 0 column, which should contain the value of COUNT(*).
// your connection code
mysqli_report(MYSQLI_REPORT_ERROR | MYSQLI_REPORT_STRICT);
$mysqli = new \mysqli('localhost', 'dbuser', 'yourdbpassword', 'db_name');
$mysqli->set_charset('utf8mb4');
// your SQL statement
$stmt = $mysqli->prepare('SELECT COUNT(*) FROM some_table WHERE col1=?');
$stmt->bind_param('s', $someVariable);
$stmt->execute();
$result = $stmt->get_result();
// now fetch 1st column of the 1st row
$count = $result->fetch_row()[0];
echo $count;
If you want to fetch all the rows, but still know the number of rows then you can use num_rows or count().
// your SQL statement
$stmt = $mysqli->prepare('SELECT col1, col2 FROM some_table WHERE col1=?');
$stmt->bind_param('s', $someVariable);
$stmt->execute();
$result = $stmt->get_result();
// If you want to use the results, but still know how many records were fetched
$rows = $result->fetch_all(MYSQLI_ASSOC);
echo $result->num_rows;
// or
echo count($rows);
Using PDO
Using PDO is much simpler. You can directly call fetchColumn() on the statement to get a single column value.
// your connection code
$pdo = new \PDO('mysql:host=localhost;dbname=test;charset=utf8mb4', 'root', '', [
\PDO::ATTR_EMULATE_PREPARES => false,
\PDO::ATTR_ERRMODE => \PDO::ERRMODE_EXCEPTION
]);
// your SQL statement
$stmt = $pdo->prepare('SELECT COUNT(*) FROM some_table WHERE col1=?');
$stmt->execute([
$someVariable
]);
// Fetch the first column of the first row
$count = $stmt->fetchColumn();
echo $count;
Again, if you need to fetch all the rows anyway, then you can get it using count() function.
// your SQL statement
$stmt = $pdo->prepare('SELECT col1, col2 FROM some_table WHERE col1=?');
$stmt->execute([
$someVariable
]);
// If you want to use the results, but still know how many records were fetched
$rows = $stmt->fetchAll();
echo count($rows);
PDO's statement doesn't offer pre-computed property with the number of rows fetched, but it has a method called rowCount(). This method can tell you the number of rows returned in the result, but it cannot be relied upon and it is generally not recommended to use.
If you're fetching data using Wordpress, then you can access the number of rows returned using $wpdb->num_rows:
$wpdb->get_results( $wpdb->prepare('select * from mytable where foo = %s', $searchstring));
echo $wpdb->num_rows;
If you want a specific count based on a mysql count query then you do this:
$numrows = $wpdb->get_var($wpdb->prepare('SELECT COUNT(*) FROM mytable where foo = %s', $searchstring );
echo $numrows;
If you're running updates or deletes then the count of rows affected is returned directly from the function call:
$numrowsaffected = $wpdb->query($wpdb->prepare(
'update mytable set val=%s where myid = %d', $valuetoupdate, $myid));
This applies also to $wpdb->update and $wpdb->delete.
As it is 2015, and deprecation of mysql_* functionality, this is a PDO-only visualization.
<?php
// Begin Vault (this is in a vault, not actually hard-coded)
$host="hostname";
$username="GuySmiley";
$password="thePassword";
$dbname="dbname";
// End Vault
$b='</br>';
try {
$theCategory="fruit"; // value from user, hard-coded here to get one in
$dbh = new PDO("mysql:host=$host;dbname=$dbname;charset=utf8", $username, $password);
$dbh->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
// prepared statement with named placeholders
$stmt = $dbh->prepare("select id,foodName from foods where category=:theCat and perishable=1");
$stmt->bindParam(':theCat', $theCategory, PDO::PARAM_STR,20);
$stmt->execute();
echo "rowCount() returns: ".$stmt->rowCount().$b; // See comments below from the Manual, varies from driver to driver
$stmt = $dbh->prepare("select count(*) as theCount from foods where category=:theCat and perishable=1");
$stmt->bindParam(':theCat', $theCategory, PDO::PARAM_STR,20);
$stmt->execute();
$row=$stmt->fetch(); // fetches just one row, which is all we expect
echo "count(*) returns: ".$row['theCount'].$b;
$stmt = null;
// PDO closes connection at end of script
} catch (PDOException $e) {
echo 'PDO Exception: ' . $e->getMessage();
exit();
}
?>
Schema for testing
create table foods
( id int auto_increment primary key,
foodName varchar(100) not null,
category varchar(20) not null,
perishable int not null
);
insert foods (foodName,category,perishable) values
('kiwi','fruit',1),('ground hamburger','meat',1),
('canned pears','fruit',0),('concord grapes','fruit',1);
For my implementation, I get the output of 2 for both echos above. The purpose of the above 2 strategies is to determine if your driver implementation emits the rowCount, and if not, to seek a fall-back strategy.
From the Manual on PDOStatement::rowCount:
PDOStatement::rowCount() returns the number of rows affected by a
DELETE, INSERT, or UPDATE statement.
For most databases, PDOStatement::rowCount() does not return the
number of rows affected by a SELECT statement. Instead, use
PDO::query() to issue a SELECT COUNT(*) statement with the same
predicates as your intended SELECT statement, then use
PDOStatement::fetchColumn() to retrieve the number of rows that will
be returned. Your application can then perform the correct action.
This is not a direct answer to the question, but in practice I often want to have an estimate of the number of rows that will be in the result set. For most type of queries, MySQL's "EXPLAIN" delivers that.
I for example use that to refuse to run a client query if the explain looks bad enough.
Then also daily run "ANALYZE LOCAL TABLE" (outside of replication, to prevent cluster locks) on your tables, on each involved MySQL server.
> SELECT COUNT(*) AS total FROM foo WHERE bar= 'value';