求解 哪里不对了

[shunzi403566]

题目：把EXKCode 相同， XShowtimes不相同的记录都选出来。
create table aaa
(
id int primary key,
exkcode varchar(10),
xshowtimes varchar(4)
)
insert into aaa values(1,'000654101','k1');
insert into aaa values(2,'000004130','k1');
insert into aaa values(3,'000654130','k1');
insert into aaa values(4,'000004130','k2');
insert into aaa values(5,'000604130','k1');
insert into aaa values(6,'000014102','k1');

Select *
From aaa a
Where id in(select id from aaa b where b.exkcode=a.exkcode and a.xshowtimes !=b.xshowtimes)

[-晴天]

create table aaa
(
id int primary key,
exkcode varchar(10),
xshowtimes varchar(4)
)  
insert into aaa values(1,'000654101','k1');
insert into aaa values(2,'000004130','k1');
insert into aaa values(3,'000654130','k1');
insert into aaa values(4,'000004130','k2');
insert into aaa values(5,'000604130','k1');
insert into aaa values(6,'000014102','k1');

Select *
From aaa a
Where exists(select 1 from aaa where exkcode=a.exkcode and xshowtimes!=a.xshowtimes)
/*id          exkcode    xshowtimes
----------- ---------- ----------
2           000004130  k1
4           000004130  k2

(2 行受影响)

*/
go
drop table aaa

[shunzi403566]

[Quote=引用 1 楼 qianjin036a 的回复:]

SQL code
create table aaa
(
id int primary key,
exkcode varchar(10),
xshowtimes varchar(4)
)
insert into aaa values(1,'000654101','k1');
insert into aaa values(2,'000004130','k1');
insert into aaa……
[/Quote]

select 1 什么意思？

[ForFumm]

1表示非空

[shunzi403566]

现在 我想知道 为什么 把id in换成exists 就能有结果了呢

[-晴天]

[Quote=引用 4 楼 shunzi403566 的回复:]
现在 我想知道 为什么 把id in换成exists 就能有结果了呢
[/Quote]
你语句的逻辑不对.

[--小F--]

exists表示存在 只要存在就满足条件了

[wlj768]

select a.* from aaa a inner join aaa b on a.exkcode = b.exkcode and a.xshowtimes <>b.xshowtimes
我用这个方法

[wlj768]

Select *
From aaa a
Where exists(select * from aaa where exkcode=a.exkcode and xshowtimes!=a.xshowtimes)

为什么要用select 1难明白