select b.* from( select uid as id from a union all select fid from a) t join b on t.id=b.id a.uid和a.fid对应在b.id中的字段, 就比如说uid是指用户的id,fid是指用户的朋友id 我想查出来用户的姓名和用户朋友的姓名,这样差肯定是不行的 把表的结构,测试数据 及你要的结果 告诉我们啊 a 表 id uid fid 1 1 2 2 3 5 b id name 1 uid1 2 uid2 3 uid3 4 uid4 5 uid5 我想要得到 a.id = 1 对应的uid的name和fid对应的name id uname fname 1 uid1 uid2 2 uid3 uid5 SQL code:
create table ta (id int,uid int,fid int) insert into ta select 1, 1, 2 u