Using pdo in php with stored procedure

You need to use bindValue instead of bindParam.

When you use bindParam, it binds the variable provided to the parameter, not the value of the variable.

So, if you do:

$x = 5;
$stmt->bindParam(1, $x, PDO::PARAM_INT);
$x = 6;
$stmt->execute(); //executes with 6 instead of 5

It's actually executed with 6 rather than 5. To do this, the method must have a reference to the variable. You cannot have a reference to a literal, so this means that bindParam cannot be used with literals (or anything you can't have a reference to).

$x = 5;
$stmt->bindValue(1, $x, PDO::PARAM_INT);
$x = 6;
$stmt->execute(); //executes with 5 instead of 6

Then:

$stmt->bindParam(1, 1, PDO::PARAM_INT); 
//invalid because there's no way to pass a literal 1 by reference
$stmt->bindValue(1, 1, PDO::PARAM_INT);
//valid