好象可以不用B表.select a.id,b.stat,a.uid,a.url from a ( select url,count(*) stat from a group by url ) b where a.url = b.url
create table tb(id int,uid int,url varchar(10))insert into tb values(1,123,'1.html') insert into tb values(2,321,'1.html') insert into tb values(3,123,'2.html') insert into tb values(4,124,'2.html') insert into tb values(5,321,'3.html')select a.id,b.stat,a.uid,a.url from tb a, ( select url,count(*) stat from tb group by url ) b where a.url = b.url drop table tb/* id stat uid url ----------- ----------- ----------- ---------- 1 2 123 1.html 2 2 321 1.html 3 2 123 2.html 4 2 124 2.html 5 1 321 3.html(所影响的行数为 5 行) */
(
select url,count(*) stat from a group by url
) b
where a.url = b.url
insert into tb values(2,321,'1.html')
insert into tb values(3,123,'2.html')
insert into tb values(4,124,'2.html')
insert into tb values(5,321,'3.html')select a.id,b.stat,a.uid,a.url from tb a,
(
select url,count(*) stat from tb group by url
) b
where a.url = b.url
drop table tb/*
id stat uid url
----------- ----------- ----------- ----------
1 2 123 1.html
2 2 321 1.html
3 2 123 2.html
4 2 124 2.html
5 1 321 3.html(所影响的行数为 5 行)
*/