Incorrect usage of UNION and ORDER BY?

Question

how can i use union and order by in mysql ?

select * from _member_facebook 
inner join _member_pts 
ON _member_facebook._fb         


        

Answer 1

With parenthesis:

(
    SELECT *
    FROM _member_facebook
    INNER JOIN _member_pts
    ON _member_facebook._fb_owner         =_member_pts._username
    WHERE _MEMBER_FACEBOOK._PROMOTE_POINT = 9
    ORDER BY RAND()
    LIMIT 2
)
UNION ALL
(
    SELECT *
    FROM _MEMBER_FACEBOOK
    INNER JOIN _MEMBER_PTS
    ON _MEMBER_FACEBOOK._FB_OWNER         =_MEMBER_PTS._USERNAME
    WHERE _MEMBER_FACEBOOK._PROMOTE_POINT = 8
    LIMIT 3
)

Said that, it isn't mandatory for MySQL to keep the inner sorting in the outer clause—though it'll probably do so since it needs to sort rows anyway to calculate the corresponding LIMIT clauses.