呵呵, 你的要求应该这样子写.SELECT * FROM t_user tA LEFT JOIN t_1 tB ON tA.u_id = tB.u_id UNION ALL SELECT * FROM t_user tA LEFT JOIN t_2 tB ON tA.u_id = tB.u_id UNION ALL SELECT * FROM t_user tA LEFT JOIN t_3 tB ON tA.u_id = tB.u_id UNION ALL SELECT * FROM t_user tA LEFT JOIN t_4 tB ON tA.u_id = tB.u_id UNION ALL SELECT * FROM t_user tA LEFT JOIN t_5 tB ON tA.u_id = tB.u_id
你的要求应该这样子写.SELECT * FROM t_user tA
LEFT JOIN t_1 tB ON tA.u_id = tB.u_id
UNION ALL
SELECT * FROM t_user tA
LEFT JOIN t_2 tB ON tA.u_id = tB.u_id
UNION ALL
SELECT * FROM t_user tA
LEFT JOIN t_3 tB ON tA.u_id = tB.u_id
UNION ALL
SELECT * FROM t_user tA
LEFT JOIN t_4 tB ON tA.u_id = tB.u_id
UNION ALL
SELECT * FROM t_user tA
LEFT JOIN t_5 tB ON tA.u_id = tB.u_id