MySQL query: Using UNION and getting row number as part of SELECT - mysql

Question

I have a union query as follows:
(SELECT t.id, t.name, c.company AS owner, t.creation_date AS date, t.notes
FROM tool t, client c
WHERE t.id_customer = '15' AND t.trash_flag = '1')
UNION
(SELECT f.id, f.name, CONCAT(m.first_name, ' ', m.last_name) AS owner, f.date, f.notes
FROM file f, meta m
WHERE ((f.acl = 0) OR (f.acl = 1 AND '1' = TRUE) OR (f.acl = 2 AND f.id = '7')) AND f.id = '15' AND f.trash_flag = '1' AND m.user_id = f.id_user)
ORDER BY 'name' 'ASC' LIMIT 0,20
Everything works fine but I have two questions:
How do I add a column to the entire result set that gives the row number
Could I do this without using UNION e.g. an advanced join?
Thanks for your time MySQL gurus!

Answer 1

I can't test it righ now but from what I found, following might work:
Reference: Row Number Variable
SQL Statement
SELECT #rownum := #rownum + 1 rownum
, t.*
FROM (
(SELECT t.id
, t.name
, c.company AS owner
, t.creation_date AS date
, t.notes
FROM tool t
, client c
WHERE t.id_customer = '15'
AND t.trash_flag = '1'
) UNION (
SELECT f.id
, f.name
, CONCAT(m.first_name, ' ', m.last_name) AS owner
, f.date
, f.notes
FROM file f
, meta m
WHERE ((f.acl = 0) OR (f.acl = 1 AND '1' = TRUE) OR (f.acl = 2 AND f.id = '7')) AND f.id = '15' AND f.trash_flag = '1' AND m.user_id = f.id_user)
)
) t
, (SELECT #rownum := 0) r
ORDER BY
'name' ASC
LIMIT 0, 20