दूसरा तरीका
SELECT cw_users.userid FROM cw_users
LEFT JOIN cw_users_data ON cw_users.userid=cw_users_data.userid
WHERE cw_users_data.userid IS NULL;
दूसरा तरीका
SELECT cw_users.userid FROM cw_users
LEFT JOIN cw_users_data ON cw_users.userid=cw_users_data.userid
WHERE cw_users_data.userid IS NULL;