SELECT `id1` , `id2`
FROM applications
WHERE `id1` = "3"
OR `id2` = "3"
UNION SELECT `id1` , `id2`
FROM duel
WHERE `id1` = "3"
OR `id2` = "3"
LIMIT 1 SELECT `id1` , `id2`
FROM applications
WHERE `id1` = "3"
OR `id2` = "3"
UNION SELECT `id1` , `id2`
FROM duel
WHERE `id1` = "3"
OR `id2` = "3"
LIMIT 1