How to modify sql_mode or Strict Mode in MySQL?

There are cases where an application or website requires disabling a restriction of the sql_mode variable in MySQL. For example, disabling "ONLY_FULL_GROUP" or "STRICT_TRANS_TABLES".

Since it is not allowed to modify the sql_mode variable on shared hosting servers, you can modify the restrictions with the following PHP code examples:

Removing all restrictions from "sql_mode" in PDO connections:

<?php
$dsn = 'mysql:host=localhost;dbname=database_name';
$username = 'username';
$password = 'password';

try {
    $pdo = new PDO($dsn, $username, $password);
    $pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);

    // Set SQL_MODE to empty
    $pdo->exec("SET sql_mode = ''");

    // Verify the change
    $stmt = $pdo->query("SELECT @@sql_mode");
    $sql_mode = $stmt->fetchColumn();
    echo "Current SQL_MODE: " . $sql_mode;

} catch (PDOException $e) {
    echo "Error: " . $e->getMessage();
}
?>

Removing all restrictions from SQL_MODE can make your application more vulnerable to errors or unexpected behaviors. It is advisable to review and understand the implications of disabling certain restrictions before doing so in a production environment.

Removing only a specific restriction from "sql_mode" in PDO connections:

In the following example, we will only remove the "ONLY_FULL_GROUP_BY" restriction.

/<?php
$dsn = 'mysql:host=localhost;dbname=database_name';
$username = 'username';
$password = 'password';

try {
    $pdo = new PDO($dsn, $username, $password);
    $pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);

    // Remove ONLY_FULL_GROUP_BY from SQL_MODE
    $pdo->exec("SET SESSION sql_mode = sys.list_drop(@@SESSION.sql_mode, 'ONLY_FULL_GROUP_BY')");

    // Verify the change
    $stmt = $pdo->query("SELECT @@SESSION.sql_mode");
    $sql_mode = $stmt->fetchColumn();
    echo "Current SQL_MODE: " . $sql_mode;

} catch (PDOException $e) {
    echo "Error: " . $e->getMessage();
}
?>