Question

sql 如何嵌套查询

能不能把 下面的2条语句合并成一条
select username,count(username) as numa from a where isdel=0 group by username order by numa desc

select username,count(username) as numb from a where isdel=0 and isx=1 group by username
能不能将上面的两条语句 联合起来输出 username,numa,numb
拜托 看清楚问题好吗?~!~!~!~!

Answer 1

select a.username,numa,numb
from (select username,count(username) as numa from a where isdel=0 group by username order by numa desc) a,
(select username,count(username) as numb from a where isdel=0 and isx=1 group by username) b
where a.username = b.username

Answer 2

java里面要实现sql嵌套查询的话,如果是javaweb项目,是可以使用hibernate框架提供的直接执行sql语句的方式来实现这样的功能.

Answer 3

select username,count(username) as numa from a where isdel=0 group by username order by numa desc

union

select username,count(username) as numb from a where isdel=0 and isx=1 group by username

Answer 4

select id,name,department表.department_name from user ,department表 where department_id = department表.id

Answer 5

select username,count(username)over(partition by username order by numa desc)
from a
where isdel=0 and isx=1

不知是不是这个意思？