is it possible to create a pdo query with a variable? Example:
$q = "SELECT COUNT (*) c FROM blogpages WHERE keywords LIKE '%test%' ";
then
$query = $db->query("$q");
$result = $query->fetch(PDO::FETCH_ASSOC);
when i do this i get an error
"Call to a member function fetch() on a non-object in C....."
i want to know is there a way to place the query in there as a variable because the query changes depending on how many OR statements are in the query
query()
PDO::query — Executes an SQL statement, returning a result set as a
PDOStatement object
And problem in your query with space between count and (*)
SELECT COUNT (*)..
^^
SO no need to fetch data just use
$q = "SELECT COUNT(*) c FROM blogpages WHERE keywords LIKE '%test%' ";
foreach ($db->query($q) as $row) {
print $row['c'] . "\t";
}
Related
I have a mysql query that targets a single column in a single row
"SELECT some_col_name FROM table_name WHERE user=:user"
After I execute the statement $stmt->execute(); how do I get this single cell directly placed into a variable with no loops? In other words how to get
from $stmt->execute();
to $col_value = 100;
I tried the 2 below, but neither worked.. The column is number 4 in the original table, but I'm assuming since in my select statement I'm selecting it only, it should be 1 when I specify the parameter for fetchColumn.
$col_value = $stmt->fetchColumn();
$col_value = $stmt->fetchColumn(0);
As you can see, I'm trying to do it in as few lines as possible.
Are you sure it's returning any rows?
$stmt->fetchColumn()
is correct way to fetch a single value, so either you probably didn't bind the :user parameter or it simply returned no rows.
$sql='SELECT some_col_name FROM table_name WHERE user=?';
$sth=$pdo_dbh->prepare($sql);
$data=array($user);
$sth->execute($data);
$result=$sth->fetchColumn();
I'm not sure why so many people mess this up:
$stmt = $dbh->prepare("SELECT `column` FROM `table` WHERE `where`=:where");
$stmt->bindValue(':where', $MyWhere);
$stmt->execute();
$SingleVar = $stmt->fetchColumn();
Make sure that you are selecting a specific column in the query and not * or you will need to specify the column order number in fetchColumn(), example: $stmt->fetchColumn(2); That usually isn't a good idea because the columns in the database may be reorganized by, someone...
This will only work properly with unique 'wheres'; fetchColumn() will not return an array.
When you want to get the last insert you add the DESC Limit 1 to the sql statement.
$sql = "SELECT `some_col_name` FROM table_name\n"
. "ORDER BY `some_col_name` DESC\n"
. "LIMIT 1";
$stmt = $conn->prepare($sql);
$result = $stmt->execute();
$row = $stmt->fetch(PDO::FETCH_ASSOC);
//convert the array content to string and store in variable
$col = implode(" ", $row);
echo $col;
Have you prepared the statement first? (Before $stmt->execute())
$stmt = $db->prepare("SELECT some_col_name FROM table_name WHERE user=:user");
You could use this:
$stmt->fetch(PDO::FETCH_COLUMN, $number_of_column);
I have the following query:
$query = <<<SQL
SELECT
year,
count(*) AS `counter`,
GROUP_CONCAT(team) AS `team_list`
FROM
team_list
WHERE year IS NOT NULL
SQL;
if (!empty($sql)) { //$sql is an array of SQL WHERE statements "a IN (a,b,c)"
$query .= ' AND ' . implode(' AND ', $sql);
}
$query .= 'GROUP BY year ORDER BY year';
/////////////////////////////
//EXECUTING THE QUERIES
/////////////////////////////
//Filter count to know how many 's' variable have to be bind to the prepared statement
$filterCount = count($teams) + count($countries) + count($years) + count($rankings); //These are my ajax elements that are also used in the $sql variable
//Data query
$queryYears = $connection->prepare($query);
$queryYears->bind_param(str_repeat('s', $filterCount), ...$teams, ...$countries, ...$years, ...$rankings);
$queryYears-> execute();
This all works very fine!
THE PROBLEM
However, once I try to enter SET SESSION group_concat_max_len = 1000000; at the beginning of my query statement I get the following error:
Fatal error: Uncaught Error: Call to a member function bind_param() on boolean
I understand that something is now wrong with my query, but when copy-pasting it to my DBMS the query can be executed without a problem.
What am I doing wrong here?
Your problem is that you are trying to execute two queries at once, and mysqli::prepare doesn't support that, so it fails and returns false. Instead, run the variable set as a separate query first:
$connection->query("SET SESSION group_concat_max_len = 1000000;") or die($connection->error);
$queryYears = $connection->prepare($query) or die($connection->error);
// etc.
Note that you should be checking the status of your calls, as I have done in the code above.
I'm having some trouble using a variable declared in PHP with an SQL query. I have used the resources at How to include a PHP variable inside a MySQL insert statement but have had no luck with them. I realize this is prone to SQL injection and if someone wants to show me how to protect against that, I will gladly implement that. (I think by using mysql_real_escape_string but that may be deprecated?)
<?php
$q = 'Hospital_Name';
$query = "SELECT * FROM database.table WHERE field_name = 'hospital_name' AND value = '$q'";
$query_result = mysqli_query($conn, $query);
while ($row = mysqli_fetch_assoc($query_result)) {
echo $row['value'];
}
?>
I have tried switching '$q' with $q and that doesn't work. If I substitute the hospital name directly into the query, the SQL query and PHP output code works so I know that's not the problem unless for some reason it uses different logic with a variable when connecting to the database and executing the query.
Thank you in advance.
Edit: I'll go ahead and post more of my actual code instead of just the problem areas since unfortunately none of the answers provided have worked. I am trying to print out a "Case ID" that is the primary key tied to a patient. I am using a REDCap clinical database and their table structure is a little different than normal relational databases. My code is as follows:
<?php
$q = 'Hospital_Name';
$query = "SELECT * FROM database.table WHERE field_name = 'case_id' AND record in (SELECT distinct record FROM database.table WHERE field_name = 'hospital_name' AND value = '$q')";
$query_result = mysqli_query($conn, $query);
while ($row = mysqli_fetch_assoc($query_result)) {
echo $row['value'];
}
?>
I have tried substituting $q with '$q' and '".$q."' and none of those print out the case_id that I need. I also tried using the mysqli_stmt_* functions but they printed nothing but blank as well. Our server uses PHP version 5.3.3 if that is helpful.
Thanks again.
Do it like so
<?php
$q = 'mercy_west';
$query = "SELECT col1,col2,col3,col4 FROM database.table WHERE field_name = 'hospital_name' AND value = ?";
if($stmt = $db->query($query)){
$stmt->bind_param("s",$q); // s is for string, i for integer, number of these must match your ? marks in query. Then variable you're binding is the $q, Must match number of ? as well
$stmt->execute();
$stmt->bind_result($col1,$col2,$col3,$col4); // Can initialize these above with $col1 = "", but these bind what you're selecting. If you select 5 times, must have 5 variables, and they go in in order. select id,name, bind_result($id,name)
$stmt->store_result();
while($stmt->fetch()){ // fetch the results
echo $col1;
}
$stmt->close();
}
?>
Yes mysql_real_escape_string() is deprecated.
One solution, as hinted by answers like this one in that post you included a link to, is to use prepared statements. MySQLi and PDO both support binding parameters with prepared statements.
To continue using the mysqli_* functions, use:
mysqli_prepare() to get a prepared statement
mysqli_stmt_bind_param() to bind the parameter (e.g. for the WHERE condition value='$q')
mysqli_stmt_execute() to execute the statement
mysqli_stmt_bind_result() to send the output to a variable.
<?php
$q = 'Hospital_Name';
$query = "SELECT value FROM database.table WHERE field_name = 'hospital_name' AND value = ?";
$statement = mysqli_prepare($conn, $query);
//Bind parameter for $q; substituted for first ? in $query
//first parameter: 's' -> string
mysqli_stmt_bind_param($statement, 's', $q);
//execute the statement
mysqli_stmt_execute($statement);
//bind an output variable
mysqli_stmt_bind_result($stmt, $value);
while ( mysqli_stmt_fetch($stmt)) {
echo $value; //print the value from each returned row
}
If you consider using PDO, look at bindparam(). You will need to determine the parameters for the PDO constructor but then can use it to get prepared statements with the prepare() method.
Hello I have a prepared statement and I need to count the number of results I get. In order to do this I use store_result and num_rows
$query = 'SELECT userId, promo, email FROM users WHERE active = ?';
$rsActivation = $db->prepare($query);
$rsActivation->bind_param('s', $actv);
$rsActivation->execute();
$rsActivation->store_result();
$totalRows = $rsActivation->num_rows;
This code manages to get me the number of rows. The problem is that if I do this I cannot use fetch() on $rsActivation. If I use fetch and not use store_result I cannot get the number of rows.
How can I accomplish both things?
Thanks
SOLVED:
Turns out my problem was I was trying to fetch the results as an associative array. Instead I used bind_result to assign values to variables. Then I was able to use store_result and num_rows to get the count and after that I used fetch() together with the variables I assigned in bind_result.
$query = 'SELECT userId, promo, email FROM users WHERE active = ?';
$rsActivation = $db->prepare($query);
$rsActivation->bind_param('s', $actv);
$rsActivation->execute();
$rsActivation->bind_result($userId, $promo, $email);
$rsActivation->store_result();
$totalRows = $rsActivation->num_rows;
while($rsActivation->fetch()){
echo "<p>". $userId ."</p>";
...
}
You can try using
...
$rsActivation->execute();
$results = $rsActivation->get_results();
$totalRows = $results->num_rows;
and you should be able to fetch using something like
$results->fetch_assoc(), $results->fetch_row(), etc.
Here's the doc for it: http://php.net/manual/en/class.mysqli-result.php
I'm trying to learn to use PDO instead of MySQLi for database access and I'm having trouble selecting data from the database. I want to use:
$STH = $DBH->query('SELECT * FROM ratings WHERE title=$title ORDER BY date ASC');
$STH->setFetchMode(PDO::FETCH_ASSOC);
while($row = $STH->fetch()) {
echo $row['title'];
}
but I'm getting this error:
Fatal error: Call to a member function setFetchMode() on a
non-object in
/home/owencont/public_html/owenstest.com/ratemystudents/index.php
on line 6
If I take out the WHERE statement it works fine. How can I select a row based on if it's value matches a variable?
Thanks,
Owen
It's likely a SQL syntax error, because you forgot to quote $title. It ended up as bareword in the query (also not even interpolated as string), resulting in an error. And your PDO connection was not configured to report errors. Use ->quote() on arguments before the ->query():
$title = $DBH->quote($title);
$STH = $DBH->query("SELECT * FROM ratings WHERE title=$title ");
Or better yet, use parameterized SQL:
$STH = $DBH->prepare("SELECT * FROM ratings WHERE title=? ");
$STH->execute(array($title));
Take a look at PDO::prepare and PDOStatement::execute. The safest way to add user content to a query is to prepare a basic statement and bind the parameter to it. Example (note the question mark in the SQL statement):
$STH = $DBH->query('SELECT * FROM ratings WHERE title=? ORDER BY date ASC');
$STH->execute( array( $title ) );
while( $row = $STH->fetch( PDO::FETCH_ASSOC ) );
Make PDO throw errors so you can see what exactly goes wrong. See How to squeeze error message out of PDO?
You are probably missing quotes around $title but this scenario really calls for prepared statements instead.
remove the variable out of the sql statement because its a php variable
$STH = $DBH->query('SELECT * FROM ratings WHERE title=' . $title . 'ORDER BY date ASC');
Use double quotes instead of single quotes as a parameter of the query-method.
The reason you're getting this error is because the query-method fails and so the $STH object isn't created. You should implement some error handling.