表A,
字段(ID........字段N)
1
2
3
4表B,
字段(ID,PID),其中PID取自表A的ID,ID才是表B的自增ID
100 1
101 1
102 2
103 2
104 3
105 3
106 3
现在希望在表A的结果最后一列增加一列用来计算表B中PID等于表A中ID的数量。
ID COUNTB
1 2
2 2
3 3
4 0
谢谢大家了。
字段(ID........字段N)
1
2
3
4表B,
字段(ID,PID),其中PID取自表A的ID,ID才是表B的自增ID
100 1
101 1
102 2
103 2
104 3
105 3
106 3
现在希望在表A的结果最后一列增加一列用来计算表B中PID等于表A中ID的数量。
ID COUNTB
1 2
2 2
3 3
4 0
谢谢大家了。
join (select pid,count(*) as n from b group by pid) b on a.id=b.pid
left join
(
select pid,count(*) as COUNTB from b group by pid
) b on a.id=b.pid
FROM tba AS A
LEFT JOIN tbb AS B
ON A.ID = B.PIDA
GROUP BY A.ID
from A
left join
(select pid,count(*) as cnt from B group by pid) B
on a.id=b.pid