Question

hello I have question on nested select in mysql. I want a working query which can achieve the goal what the dummy query below intends to achieve:

select t1.col1 from t1
  where t1.col2 in
  (select t3.col2, t3.col3 from t3
     order by t3.col3 limit NUM)

Well basically speaking, t1.col2 should be in the nest selected t3.col2, but the nested select should order by another column which is t3.col3.

Answer 1

Unfortunatenly, MySQL does not support LIMIT for queries used with IN.

Try this:

SELECT  col1
FROM    (
        SELECT  DISTINCT col2
        FROM    (
                SELECT  col2
                FROM    t3
                ORDER BY
                        col3
                LIMIT   5
                ) q
        ) q
JOIN    t1
USING   (col2)