如果选field_d = 1的话,只有如下一条结果。 field_a field_b field_c field_d 3 111 6 1 select * from a, b where a.field_a = b.field_a and field_d=1 and field_b = 111如果选field_d = 2的话,只有如下一条结果。 field_a field_b field_c field_d 2 234 5 2 select * from a, b where a.field_a = b.field_a and field_d=2 and field_b = 234如果选field_d = 3的话,只有如下一条结果。 field_a field_b field_c field_d 1 123 3 3 select * from a, b where a.field_a = b.field_a and field_d=3 and field_b = 123
假设A表结构
field_a | field_b
1 123
2 234
3 111
假设B表结构
field_c | field_d | field_a
1 1 1
2 2 1
3 3 1
4 1 2
5 2 2
6 1 3
如果选field_d = 1的话,只有如下一条结果。
field_a field_b field_c field_d
3 111 6 1
如果选field_d = 2的话,只有如下一条结果。
field_a field_b field_c field_d
2 234 5 2
如果选field_d = 3的话,只有如下一条结果。
field_a field_b field_c field_d
1 123 3 3请问,这样的SQL该怎么写
field_a field_b field_c field_d
3 111 6 1
select * from a, b where a.field_a = b.field_a and field_d=1 and field_b = 111如果选field_d = 2的话,只有如下一条结果。
field_a field_b field_c field_d
2 234 5 2
select * from a, b where a.field_a = b.field_a and field_d=2 and field_b = 234如果选field_d = 3的话,只有如下一条结果。
field_a field_b field_c field_d
1 123 3 3
select * from a, b where a.field_a = b.field_a and field_d=3 and field_b = 123