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();
I am using php and mysql to create a page that displays all of the jobs we have in the database. The data is shown is a table and when a row is clicked a modal window triggers with the information of the clicked job inside. At the top of the page I want a simple counter that shows amount of paid jobs, invoiced jobs etc etc. I am using the code below but having no luck...
<?php
$con = mysql_connect("localhost","databaseusername","password");
if (!$con) {
die('Could not connect: ' . mysql_error());
}
mysql_select_db("databasename", $con);
$result = mysql_query("select count(1) FROM jobslist");
$row = mysql_fetch_array($result);
$total = $row[0];
mysql_close($con);
?>
This code as far as I am aware is counting the amount of INT columns set to 1 rather than 0. No matter what I try I can't seem to get it to count the amount of 'paid' items in the database or 'invoiced' etc etc.
Once the count function is complete currently I am echoing out the outcome as below:
<?php echo "" . $total;?>
I am sure I am overlooking something simple, but any help is appreciated.
EDIT: TABLE STRUCTURE INCLUDED
http://i.stack.imgur.com/hcMJV.png
Assuming a column called paid you could restructure the query similar to the following. If you needed to sum the amounts involved that requires additional tweaking.
$result = mysql_query("select
( select count(*) from `jobslist` where `paid`=1 ) as 'paid',
( select count(*) from `jobslist` where `paid`=0 ) as 'unpaid'
from jobslist");
$rows = mysql_num_rows( $result );
while( $rs=mysql_fetch_object( $result ) ){
$paid=$rs->paid;
$unpaid=$rs->unpaid;
echo 'Total: '.$rows.'Paid: '. $paid.' Unpaid: '.$unpaid;
}
When I do this I usually name the COUNT result. Try this out:
$result = mysql_query("SELECT COUNT(*) AS total_rows FROM jobslist;");
$row = mysql_fetch_array($result);
$total = $row['total_rows'];
If you do not want to name the COUNT result, then give the following a go:
$result = mysql_query("SELECT COUNT(*) FROM jobslist;");
$row = mysql_fetch_array($result);
$total = $row['COUNT(*)'];
select count(1) FROM jobslist
This code as far as I am aware is counting the amount of INT columns set to 1 rather than 0.
No, this is just counting rows in your table and not filtering. If you want to count something with a specific filter you have to add that filter condition:
SELECT COUNT(*) AS `MyCount`
FROM `joblist`
WHERE `MyColumn` = 1; -- assuming MyColumn contains the INT you're looking for
You should stop using mysql_* functions. These extensions have been removed in PHP 7. Learn about prepared statements for PDO and MySQLi and consider using PDO, it's really pretty easy.
First you should change deprecated mysql_... to mysqli_... (look here how to). But it's not the reason you fail.
Unlike you seem to suppose, COUNT(1) will not look for an INT column having value 1.
Instead you must use COUNT(*) or COUNT(a_column_name) (same result), with adding a WHERE clause stating which condition is involved.
Here you seem wanting to count records where a given column (say the_column) has value 1. So you should:
SELECT COUNT(*)
FROM jobslist
WHERE the_column = 1
Last point: you don't need echo "" . in <?php echo "" . $total;?>.
Merely write <?php echo $total;?>.
There are numerous discussions on SO regarding how to get the number of rows returned when running a SELECT query using PDO. While most (including the PHP manual) suggest using two queries, with the first running COUNT(), I haven't seen one that suggested how to easily do this using prepared statements with WHERE clauses.
How do I most-efficiently (both in processing and number of lines of code) run a COUNT() using the same WHERE clause? The prepared query already has the columns specified. fetchAll() won't work here because that won't scale; if I have to return millions of rows, processing it using fetchAll would be super slow.
For example, without the count:
$sql = "SELECT
FirstName,
LastName
FROM
People
WHERE
LastName = :lastName";
$query = $pdoLink->prepare($sql);
$query->bindValue(":lastName", '%Smith%');
$query->execute();
while($row = $query->fetch(PDO::FETCH_ASSOC)) {
echo $row['FirstName'] . " " . $row['LastName'];
}
I looked at just adding COUNT(ID) to the SELECT clause, and having it be just one query, but it looks like there is no real good way (or not database-specific way) of rewinding the fetch() once I get a row from it.
Another solution could be making the WHERE clause it's own variable that is built. But, that doesn't seem very efficient. It's preparing two queries, binding the values all over again, and executing it.
So something like:
$whereClause = " WHERE
LastName = :lastName";
$rowsSql = "SELECT
COUNT(ID) As NumOfRows
FROM
People " . $whereClause;
$rowsQuery = $pdoLink->prepare($sql);
$rowsQuery->bindValue(":lastName", '%Smith%');
$rowsQuery->execute();
if ($rowsQuery->fetchColumn() >= 1)
//Prepare the original query, bind it, and execute it.
$sql = "SELECT
FirstName,
LastName
FROM
People " . $whereClause;
$query = $pdoLink->prepare($sql);
$query->bindValue(":lastName", '%Smith%');
$query->execute();
while($row = $query->fetch(PDO::FETCH_ASSOC)) {
echo $row['FirstName'] . " " . $row['LastName'];
}
}
else
{
//No rows found, display message
echo "No people found with that name.";
}
When using MySQL, PDOStatement::rowCount() returns the number of rows in the result set. It actually calls the underlying mysql_num_rows() C function to populate the value. No need for multiple queries or any other messing around.
This is true of MySQL, but this behaviour cannot be relied on for other drivers (others may support it but it's not guaranteed, I'm not familiar with others enough to say for sure either way). But since your question regards specifically MySQL, it should serve your purposes.
Try this built-in PDO function;
$query->rowCount();
This is the code giving me issue - I'm trying to update multiple records with one insert. The values are put in an array and using a foreach I've prepared the mysqli update. But it's not working. Just gives a MySqli error about the syntax on the update.
foreach($users as $user){
if(empty($course)) continue;
$query_string .= " SET group_id='$group_id' WHERE user_id='".$user."'; ";
}
$query_string = substr($query_string,0,-1);
$query = "UPDATE users" . $query_string;
$result = mysqli_query($dbc, $query) or trigger_error("Query: $query");
The error it gives is:
You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'SET group_id='10' WHERE user_id='5''. I think it's the ';' in the middle that mysqli isn't accepting.
Assuming you've got more than one user, your query will look like
UPDATE users SET ... SET ... SET ... SET ...
which is incorrect. You cannot do updates to multiple rows in this fashion. Either do multiple queries, each updating one student, or you'll have to build a huge case/if block to do this in a single query.
You'd be better off doing the multiple queries, as you'll probably spend more time BUILDING the monolithic query than it'd take to run the individual updates.
How about WHERE...IN
UPDATE foo SET bar = 0 WHERE baz IN (1,2,3,4,5,6)
(presuming that you are setting them all to the same group ID, which is not clear in the context provided)
try this code:
<?php
$queries = array();
foreach($users as $user){
if(empty($course)) continue;
$queries[] = "update users set group_id = '" . mysql_real_escape_string($group_id) . "' where user_id = '" . mysql_real_escape_string($user) . "'";
}
array_map('mysql_query', $queries);
?>
Your problem is that you don't separate the different users with ;. Since you're updating all users to have the same group (I'm not sure this is the case, otherwise it will get much more complex) you can simply expand the criteria with OR. Your resulting query would look something like the following:
UPDATE users SET group_id='42' WHERE user_id='1' OR user_id='2' OR user_id='3';
Another solution would be to use WHERE ... IN. Here's an example of that:
UPDATE users SET group_id='42' WHERE user_id IN (1, 2, 3);