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phppdoprepared-statement

PHP PDO prepared statement IN() array


From the PHP Manual :

You cannot bind multiple values to a single named parameter in, for example, the IN() clause of an SQL statement.

But can you use multiple values using question mark parameter markers? Or do you have to prepare() a new statement every time the number of values changes?

SELECT * FROM `table` WHERE `column` IN(?)

If this is allowed how do you make it work?

EDIT: The two previous questions indicated were both about named variables, which the manual says can't be bound to multiple parameters. I was asking about question mark (anonymous) variables.


Solution

  • Here's some code I whipped up to simulate the desired outcome:

    <?php
    function preprepare(&$query, &$data) {
        preg_match_all('/\?/', $query, $matches, PREG_OFFSET_CAPTURE);
        $num = count($matches[0]);
        for ($i = $num; $i;) {
            --$i;
            if (array_key_exists($i, $data) && is_array($data[$i])) {
                $query = substr_replace($query, implode(',', array_fill(0, count($data[$i]), '?')), $matches[0][$i][1], strlen($matches[0][$i][0]));
                array_splice($data, $i, 1, $data[$i]);
            }
        }
    }
    
    $query = 'SELECT * FROM `table` WHERE `col1` = ? AND `col2` IN(?) AND `col3` = ? AND `col4` IN(?)';
    $data = array('foo', array(1, 2, 3), 'bar', array(4, 2));
    preprepare($query, $data);
    var_dump($query, $data);
    ?>
    

    It outputs:

    array (size=2)
      0 => string 'SELECT * FROM `table` WHERE `col1` = ? AND `col2` IN(?,?,?) AND `col3` = ? AND `col4` IN(?,?)' (length=93)
      1 => 
        array (size=7)
          0 => string 'foo' (length=3)
          1 => int 1
          2 => int 2
          3 => int 3
          4 => string 'bar' (length=3)
          5 => int 4
          6 => int 2
    

    The query and data can then be used in a normal PDO prepared statement. I don't know if it accounts for all PDO magic niceness but it works pretty well so far.