SQL Server 2005 技术内幕 TSQL查询学习笔记chapter4之三排名函数Row_number()和分页应用

SQL2005排名函数Row_Number()
定义:只能出现在Select或者Order By子句中

格式:

Row_Number() Over([Partition By col_list] Order By col_list)

解释:Over([分区列] 排序列)

为了计算排名值,优化器需要先按分区列再按排序列对数据排序

创建示例表



插入10W条数据

declare @i int,

@Title nvarchar(200),

@Content nvarchar(MAX),

@CreateAuthor varchar(50);

set @i=1

while @i<100001

begin

set @Title='标题'+convert(nvarchar(200),@i)

set @Content='内容为'+convert(nvarchar(MAX),@i)+'的帖子'

set @CreateAuthor='sina'

insert into Topics (Title,[Content],CreateAuthor) values(@Title,@Content,@CreateAuthor)

set @i=@i+1

end

创建存储过程Paging

CREATE PROCEDURE Paging

(@PageIndex INT,--页索引,从开始

@PageSize INT,--每页显示大小

@Count INT OUTPUT)--记录总数

AS

-- 创建临时表

Create Table #TopicsTemp

(RowNumber INT,

Id int,

Title nvarchar(200),

[Content] nvarchar(MAX),

CreateDate DateTime,

CreateAuthor varchar(50))

--行号上创建聚集索引

Create Unique Clustered Index idx_rn ON #TopicsTemp(RowNumber)

-- 填充临时表

INSERT INTO #TopicsTemp

SELECT ROW_NUMBER() OVER (ORDER BY Topics.Id),

Id,Title,[Content],CreateDate,CreateAuthor From Topics

-- 返回临时表中的记录总数

SELECT @Count = COUNT(id) FROM #TopicsTemp

-- 从表变量查询数据

SELECT Id,Title,[Content],CreateDate,CreateAuthor

FROM #TopicsTemp

WHERE RowNumber > (@PageIndex - 1) * @PageSize

AND RowNumber <= @PageIndex * @PageSize