一条mssql 语句 行转列

[hai_na_bai_chuan_]

x y
------------------------
1 a
2 b
3 c
4 d


结果
a1 a2 a3 a4
---------------------
a b c d

[LongRui888]

试试这个：

select max(case when x = 1 then y end) as a1,
       max(case when x = 2 then y end) as a2,
       max(case when x = 3 then y end) as a3,
       max(case when x = 4 then y end) as a4       
from 
(
select 1  as x ,'a' as y union all
select 2   ,'b' union all
select 3   ,'c' union all
select 4   ,'d'
)v
/*
a1	a2	a3	a4
a	b	c	d
*/

[LongRui888]

其实行转列，就是分组（一般会有group by xx字段）之后，通过聚合函数，一般是max，min，如果同时有计数、求和，就用count，sum。

[hai_na_bai_chuan_]

select max(case when x = 1 then y end) as a1, max(case when x = 2 then y end) as a2, max(case when x = 3 then y end) as a3, max(case when x = 4 then y end) as a4 from v --- group by y 我也很纳闷啊，这么简单的语句,画蛇添足加了 group by y 谢谢了，讲的十分详细

[中国风]

这语句不能固定写死，应该 用动态