建立表:
CREATE TABLE [TestTable] (
[ID] [int] IDENTITY (1, 1) NOT NULL ,
[FirstName] [nvarchar] (100) COLLATE Chinese_PRC_CI_AS NULL ,
[LastName] [nvarchar] (100) COLLATE Chinese_PRC_CI_AS NULL ,
[Country] [nvarchar] (50) COLLATE Chinese_PRC_CI_AS NULL ,
[Note] [nvarchar] (2000) COLLATE Chinese_PRC_CI_AS NULL
) ON [PRIMARY]
GO
插入資料:(2萬條,用更多的資料測試會明顯一些)
SET IDENTITY_INSERT TestTable ON
declare @i int
set @i=1
while @i<=20000
begin
insert into TestTable([id], FirstName, LastName, Country,Note) values(@i, 'FirstName_XXX','LastName_XXX','Country_XXX','Note_XXX')
set @i=@i+1
end
SET IDENTITY_INSERT TestTable OFF
-------------------------------------
分頁方案一:(利用Not In和SELECT TOP分頁)
語句形式:
SELECT TOP 10 *
FROM TestTable
WHERE (ID NOT IN
(SELECT TOP 20 id
FROM TestTable
ORDER BY id))
ORDER BY ID
SELECT TOP 頁大小 *
FROM TestTable
WHERE (ID NOT IN
(SELECT TOP 頁大小*頁數 id
FROM 表
ORDER BY id))
ORDER BY ID
-------------------------------------
分頁方案二:(利用ID大於多少和SELECT TOP分頁)
語句形式:
SELECT TOP 10 *
FROM TestTable
WHERE (ID >
(SELECT MAX(id)
FROM (SELECT TOP 20 id
FROM TestTable
ORDER BY id) AS T))
ORDER BY ID
SELECT TOP 頁大小 *
FROM TestTable
WHERE (ID >
(SELECT MAX(id)
FROM (SELECT TOP 頁大小*頁數 id
FROM 表
ORDER BY id) AS T))
ORDER BY ID
-------------------------------------
分頁方案三:(利用SQL的遊標預存程序分頁)
create procedure XiaoZhengGe
@sqlstr nvarchar(4000), --查詢字串
@currentpage int, --第N頁
@pagesize int --每頁行數
as
set nocount on
declare @P1 int, --P1是遊標的id
@rowcount int
exec sp_cursoropen @P1 output,@sqlstr,@scrollopt=1,@ccopt=1,@rowcount=@rowcount output
select ceiling(1.0*@rowcount/@pagesize) as 總頁數--,@rowcount as 總行數,@currentpage as 當前頁
set @currentpage=(@currentpage-1)*@pagesize+1
exec sp_cursorfetch @P1,16,@currentpage,@pagesize
exec sp_cursorclose @P1
set nocount off
其它的方案:如果沒有主鍵,可以用暫存資料表,也可以用方案三做,但是效率會低。
建議最佳化的時候,加上主鍵和索引,查詢效率會提高。
通過SQL 查詢分析器,顯示比較:我的結論是:
分頁方案二:(利用ID大於多少和SELECT TOP分頁)效率最高,需要拼接SQL語句
分頁方案一:(利用Not In和SELECT TOP分頁) 效率次之,需要拼接SQL語句
分頁方案三:(利用SQL的遊標預存程序分頁) 效率最差,但是最為通用
在實際情況中,要具體分析。
以下是另一個預存程序的例子.
通常用普通的SQL語句查詢資料,在資料量少的情況下速度上沒什麼感覺,一旦數居量很大之後,速度會明顯變慢,因為大量的資料在網路中傳輸會花掉不少的時間,如果使用了分頁查詢資料,只反回有用的資料,把不需要的資料排除後,傳輸速度會快很多,如下是一個SQL分頁的預存程序,本過程是以SQL內建的 Northwind 資料庫為例寫的,可以根據自已的需要隨意更改
CREATE PROCEDURE [GetCustomersDataPage]
@PageIndex INT, --頁號
@PageSize INT, --頁數
@RecordCount INT OUT, --記錄數
@PageCount INT OUT --頁數
AS
SELECT @RecordCount = COUNT(*) FROM Customers
SET @PageCount = CEILING(@RecordCount * 1.0 / @PageSize)
DECLARE @SQLSTR NVARCHAR(1000)
IF @PageIndex = 0 OR @PageCount <= 1
SET @SQLSTR ='SELECT TOP '+STR( @PageSize )+' CustomerID, CompanyName,Address,Phone FROM Customers ORDER BY CustomerID DESC'
ELSE IF @PageIndex = @PageCount - 1
SET @SQLSTR =' SELECT * FROM ( SELECT TOP '+STR( @RecordCount - @PageSize * @PageIndex )+' CustomerID, CompanyName,Address,Phone FROM Customers ORDER BY CustomerID ASC ) TempTable ORDER BY CustomerID DESC'
ELSE
SET @SQLSTR =' SELECT TOP '+STR( @PageSize )+' * FROM ( SELECT TOP '+STR( @RecordCount - @PageSize * @PageIndex )+' CustomerID, CompanyName,Address,Phone FROM Customers ORDER BY CustomerID ASC ) TempTable ORDER BY CustomerID DESC'
EXEC (@SQLSTR)
GO