MySQL integer field is returned as string in PHP

Question

When you select data from a MySQL database using PHP the datatype will always be converted to a string. You can convert it back to an integer using the following code:

$id = (int) $row['userid'];

Or by using the function intval():

$id = intval($row['userid']);

Use the mysqlnd (native driver) for php.

If you're on Ubuntu:

sudo apt-get install php5-mysqlnd
sudo service apache2 restart

If you're on Centos:

sudo yum install php-mysqlnd
sudo service httpd restart

The native driver returns integer types appropriately.

As @Jeroen has pointed out, this method will only work out-of-the-box for PDO.
As @LarsMoelleken has pointed out, this method will work with mysqli if you also set the MYSQLI_OPT_INT_AND_FLOAT_NATIVE option to true.

Example:

$mysqli->options(MYSQLI_OPT_INT_AND_FLOAT_NATIVE, TRUE);

Easiest Solution I found:

You can force json_encode to use actual numbers for values that look like numbers:

json_encode($data, JSON_NUMERIC_CHECK) 

(since PHP 5.3.3).

Or you could just cast your ID to an int.

$row = $result->fetch_assoc();
$id = (int) $row['userid'];

My solution is to pass the query result $rs and get a assoc array of the casted data as the return:

function cast_query_results($rs) {
    $fields = mysqli_fetch_fields($rs);
    $data = array();
    $types = array();
    foreach($fields as $field) {
        switch($field->type) {
            case 3:
                $types[$field->name] = 'int';
                break;
            case 4:
                $types[$field->name] = 'float';
                break;
            default:
                $types[$field->name] = 'string';
                break;
        }
    }
    while($row=mysqli_fetch_assoc($rs)) array_push($data,$row);
    for($i=0;$i<count($data);$i++) {
        foreach($types as $name => $type) {
            settype($data[$i][$name], $type);
        }
    }
    return $data;
}

Example usage:

$dbconn = mysqli_connect('localhost','user','passwd','tablename');
$rs = mysqli_query($dbconn, "SELECT * FROM Matches");
$matches = cast_query_results($rs);
// $matches is now a assoc array of rows properly casted to ints/floats/strings

No. Regardless of the data type defined in your tables, PHP's MySQL driver always serves row values as strings.

You need to cast your ID to an int.

$row = $result->fetch_assoc();
$id = (int) $row['userid'];

I like Chad's answer, especially when the query results will be passed on to javascript in a browser. Javascript deals cleanly with numeric like entities as numbers but requires extra work to deal with numeric like entities as strings. i.e. must use parseInt or parseFloat on them.

Building on Chad's solution I use this and it is often exactly what I need and creates structures that can be JSON encoded for easy dealing with in javascript.

while ($row = $result->fetch_assoc()) {
    // convert numeric looking things to numbers for javascript
    foreach ($row as &$val) {
        if (is_numeric($val))
            $val = $val + 0;
    }
}

Adding a numeric string to 0 produces a numeric type in PHP and correctly identifies the type so floating point numbers will not be truncated into integers.