返回信息流有两个表，分别表示用户的发图记录和发帖记录，写一SQL语句，求发帖数最少的用户发的图片数，以下是表结构，其中两个表以img_user,rev_user关联。
Img_id Img_user
1.jpg 2
2.gif 3
3.png 2
表image
Rev_id Rev_user
0 1
1 2
2 2
表revision
如：select _______ as user_id, _______ as rev_count, _______ as img_count from ______
高手请指教，多谢。
这是一条镜像帖。来源：北邮人论坛 / database / #3913同步于 2009/10/14
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搜狐数据库SQL考题
liuge007
2009/10/14镜像同步5 回复
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5 条回复
--oracle
select count(*)
from image
where img_user
in (
select t1.rev_user
from (
select rev_user,count(*) as rev_count
from revision
group by rev_user
order by rev_count asc) as t1
where rownum=1
)--发帖最少的者
)
--通用
select count(*)
from image
where img_user
in (
select t2.rev_user
from (select min(rev_count)
from (
select rev_user,count(*) as rev_count
from revision
group by rev_user
)
) as t1,
(select rev_user,count(*) as rev_count
from revision
group by rev_user
) as t2
where t1.rev_count=t2.rev_count
)
各横线的值
如：select _______ as user_id, _______ as rev_count, _______ as img_count from ______
第一个：
select t2.rev_user
from (select min(rev_count)
from (
select rev_user,count(*) as rev_count
from revision
group by rev_user
)
) as t1,
(select rev_user,count(*) as rev_count
from revision
group by rev_user
) as t2
where t1.rev_count=t2.rev_count
第二个：
select min(rev_count)
from (
select rev_user,count(*) as rev_count
from revision
group by rev_user
)
第三个：
select count(*)
from image
where img_user
in (
select t2.rev_user
from (select min(rev_count)
from (
select rev_user,count(*) as rev_count
from revision
group by rev_user
)
) as t1,
(select rev_user,count(*) as rev_count
from revision
group by rev_user
) as t2
where t1.rev_count=t2.rev_count
)
第四个：
dual
select count(*) from image
where img_user=(
select rev_user from
(select rev_user,count(*) as rev_count from revision group by rev_user) as t1
group by t1.rev_user
order by min(rev_count)
limit 1
);