三表联合查询,如何组织sql才能执行的快
三表联合查询,如何组织sql才能执行的快
日期:2021-07-13 02:28:19 人气:1
SELECT * FROM a
INNER JOIN b on b.b_id = a.b_id
INNER JOIN c ON c.c_id = a.c_id
WHERE b.b_v=b1 AND c_v=c3 AND c_v = c4
INNER JOIN b on b.b_id = a.b_id
INNER JOIN c ON c.c_id = a.c_id
WHERE b.b_v=b1 AND c_v=c3 AND c_v = c4