Need help in creating CriteriaQuery - jpa

Question

First of all, I would like to know if it is possible to do?
Below is my query and I am trying to build using criteria.
SELECT CONCAT('record-', rl.record_id) AS tempId,
'sloka' AS type,
rl.record_id AS recordId,
rl.title AS title,
rl.locale as locale,
rl.intro AS intro,
rl.title AS localetitle,
NULL AS audioUrl,
lp.name AS byName,
lp.person_id AS byId,
lp.name AS onName,
lp.person_id AS onId
FROM record_locale rl
LEFT JOIN record r ON rl.record_id = r.record_id
LEFT JOIN locale_person lp ON r.written_on = lp.person_id
WHERE rl.title LIKE :title
AND rl.locale = :locale
AND lp.locale = :locale
UNION
SELECT CONCAT('lyric-', s.song_id) AS tempId,
'bhajan' AS type,
s.song_id AS recordId,
s.title,
l.locale as locale,
NULL AS intro,
l.title AS localetitle,
s.audio_url AS audioUrl,
lpb.name AS byName,
lpb.person_id AS byId,
lpo.name AS onName,
lpo.person_id AS onId
FROM song s
LEFT JOIN locale_person lpb
ON (s.written_by = lpb.person_id AND lpb.locale = :locale)
LEFT JOIN locale_person lpo
ON (s.written_on = lpo.person_id AND lpo.locale = lpb.locale)
INNER JOIN lyric l
ON (l.locale = lpb.locale AND l.song_id = s.song_id)
WHERE s.title LIKE :title AND s.approved_by IS NOT NULL
ORDER BY localeTitle ASC
// END
Based on few conditions, I might need to have union of both queries or just individual query without union.

Answer 1

Converting the SQL to JPQL is usually a good first step, as we can't quite tell what these tables map to, or what you are expecting to get back. If it is possible to do in JPQL, it should be possible with a criteria query. Except in this case: JPA/JPQL does not have the union operator so it won't work in straight JPA, but some providers such as EclipseLink have support. See:
UNION to JPA Query
and
http://www.eclipse.org/eclipselink/documentation/2.5/jpa/extensions/j_union.htm