Simple script for checking foreign keys consistent

mysqlfkc.php

<?php

/**
 * usage:
 *   php mysqlfkc.php mysql://user:pass@host/database
 */
 
require_once 'vendor/autoload.php';

$conn = \Doctrine\DBAL\DriverManager::getConnection([
    'url' => $argv[1],
]);

$sql = $conn->createQueryBuilder()
    ->select(
        'TABLE_SCHEMA',
        'TABLE_NAME',
        'COLUMN_NAME',
        'REFERENCED_TABLE_SCHEMA',
        'REFERENCED_TABLE_NAME',
        'REFERENCED_COLUMN_NAME'
    )
    ->from('information_schema.KEY_COLUMN_USAGE')
    ->where('REFERENCED_TABLE_SCHEMA IS NOT NULL')
    ->andWhere('TABLE_SCHEMA = ?')
    ->getSQL()
;

$checks = $conn->fetchAll($sql, [$conn->getDatabase()]);

$pat = '
SELECT
    COUNT(*)
  FROM
    %1$s.%2$s AS a
  LEFT JOIN
      %4$s.%5$s AS b
    ON
      a.%3$s = b.%6$s
  WHERE
      a.%3$s IS NOT NULL
      AND
      b.%6$s IS NULL
';
foreach($checks as $check) {
    $sql = sprintf(
        $pat,
        $check['TABLE_SCHEMA'],
        $check['TABLE_NAME'],
        $check['COLUMN_NAME'],
        $check['REFERENCED_TABLE_SCHEMA'],
        $check['REFERENCED_TABLE_NAME'],
        $check['REFERENCED_COLUMN_NAME']
    );

    $count = $conn->fetchColumn($sql);

    if($count > 0) {
        print_r($check);
    }
}