privot函数使用

语法：

table_source

PIVOT(

聚合函数（value_column）

FOR pivot_column

IN(<column_list>)

)

将列转化为行

写个小示例 ：比如按人统计该月份的考勤小时数

USE [test]
GO

/****** Object:  Table [dbo].[KaoQin]    Script Date: 07/06/2017 15:44:34 ******/
SET ANSI_NULLS ON
GO

SET QUOTED_IDENTIFIER ON
GO

CREATE TABLE [dbo].[KaoQin](
    [autoId] [int] IDENTITY(1,1) NOT NULL,
    [userName] [nvarchar](50) NULL,
    [dt] [datetime] NULL,
    [hour] [int] NULL,
 CONSTRAINT [PK_KaoQin] PRIMARY KEY CLUSTERED
(
    [autoId] ASC
)WITH (PAD_INDEX  = OFF, STATISTICS_NORECOMPUTE  = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS  = ON, ALLOW_PAGE_LOCKS  = ON) ON [PRIMARY]
) ON [PRIMARY]

GO

然后新增一点儿测试数据

declare @count int
set @count=5

declare @i int
set @i=0

declare @riqi datetime
set @riqi=GETDATE()

while  @i<@count
begin

    set @riqi=dateadd(day,1,@riqi)

    insert into dbo.KaoQin values('王二',@riqi, cast(RAND()*10 as int))
    set @i=@i+1
end

最后数据是这样的

传统的办法当然也可以解决，如下

select
SUM( case  when userName='张三' then hour else 0 end )as '张三',
SUM( case when userName='李四' then hour else 0 end ) as '李四',
SUM( case when userName='王二' then hour else 0 end ) as '王二'
 from dbo.KaoQin

哪些下面重点来了 我们用pivot