mysql find_in_set函数和on一起用
two表:

three表:

SELECT GROUP_CONCAT(three.three_name), two.two_id FROM two LEFT JOIN three ON FIND_IN_SET( three.three_id, two.three_ids ) GROUP BY two.two_id

two表:

three表:

SELECT GROUP_CONCAT(three.three_name), two.two_id FROM two LEFT JOIN three ON FIND_IN_SET( three.three_id, two.three_ids ) GROUP BY two.two_id
