select t1.a, t1.b, sum(t1.c),count(1)
from (select t.a, t.b, t.c from t where t.b is not null) t1
group by t1.a, t1.b
今天遇到上面结构的sql,我在子查询那里已经限制not null,为什么最后出来的结果里面b字段还是有空值的?
select t1.a, t1.b, sum(t1.c),count(1)
from (select t.a, t.b, t.c from t where t.b is not null) t1
group by t1.a, t1.b
今天遇到上面结构的sql,我在子查询那里已经限制not null,为什么最后出来的结果里面b字段还是有空值的?