SET @access_role_permission_version_sql = (
    SELECT IF(COUNT(*) > 0,
        'ALTER TABLE workbench_access_roles DROP COLUMN permission_version',
        'SELECT 1')
    FROM information_schema.COLUMNS
    WHERE TABLE_SCHEMA = DATABASE()
      AND TABLE_NAME = 'workbench_access_roles'
      AND COLUMN_NAME = 'permission_version'
);
PREPARE access_role_permission_version_stmt FROM @access_role_permission_version_sql;
EXECUTE access_role_permission_version_stmt;
DEALLOCATE PREPARE access_role_permission_version_stmt;