mysql - 我怎样才能得到想要的结果？

Question

需要mysql语句的帮助

P_ID |  P_NAME 

1   P1
2   P2



PT_ID | P_ID | S_ID
1   1   1
1   1   2
1   1   3
1   2   1
1   2   2
1   2   3
1   2   4

要求的结果:

P_ID | P_NAME | S_ID    
1   P1  3
2   P2  4

Answer 1

Select t1.P_ID, t1.P_Name, count(t2.SID) as S_ID
     FROM table1 t1 join table t2 on t1.P_ID = t2.P_ID
          Group by t2.P_ID