表1
ID T1
1 A
2 B
3 C
表2
ID Copy_T3 Copy_T1
1 D A
2 E B
3 F C
4 D B
5 D C
6 E C
表3
ID T3
1 D
2 E
3 F如何知道表3里的D 查询关联的表1里有什么?LOOP?怎么个写法?或好点的办法~
ID T1
1 A
2 B
3 C
表2
ID Copy_T3 Copy_T1
1 D A
2 E B
3 F C
4 D B
5 D C
6 E C
表3
ID T3
1 D
2 E
3 F如何知道表3里的D 查询关联的表1里有什么?LOOP?怎么个写法?或好点的办法~
select 表1.* from 表1 where 表1.t1 in (select 表2.Copy_T1 from 表2 where copy3_t3 = 'D')
insert into a values(1, 'A')
insert into a values(2, 'B')
insert into a values(3, 'C')
create table b(ID int, Copy_T3 varchar(10), Copy_T1 varchar(10))
insert into b values(1, 'D', 'A')
insert into b values(2, 'E', 'B')
insert into b values(3, 'F', 'C')
insert into b values(4, 'D', 'B')
insert into b values(5, 'D', 'C')
insert into b values(6, 'E', 'C')
create table c(ID int,T3 varchar(10))
insert into c values(1, 'D')
insert into c values(2, 'E')
insert into c values(3, 'F')
goselect a.* from a where a.t1 in (select copy_t1 from b where copy_t3 = 'd')
/*
ID T1
----------- ----------
1 A
2 B
3 C
(所影响的行数为 3 行)
*/
--c表全部
select a.* from a where a.t1 in (select copy_t1 from b where copy_t3 in (select t3 from c))
/*
ID T1
----------- ----------
1 A
2 B
3 C
(所影响的行数为 3 行)
*/
drop table a,b,c