id dept Person Rating
-------------------------------------------
1 ece p1 R1
2 ece p2 t1
3 eee P3 R2
4 eee p4 M
5 Civil P5 R2
6 Civil P6 t2
7 Civil P7 t2
8 Mech p8 R2
9 Mech P9 NULL
10 IT P10 R2J
11 IT P11 T2
12 IT P12 T2
我想获取其部门的评分至少具有一个像'P%'和一个像'T%'的行。
答案 0 :(得分:1)
一个相当直接的方法使用exists
:
select t.*
from t
where exists (select 1 from t t2 where t2.dept = t.dept and t2.rating like 'P%') and
exists (select 1 from t t2 where t2.dept = t.dept and t2.rating like 'T%') ;