基本原则:能用表变量就用表变量.实在不行才使用临时表
表变量主要是开销系统的内存,而临时表则使用tempdb.对于小数据量的中间数据存储,可以使用表变量,而当需要临时保存的数据很大时,建议使用临时表。
用法:
--创建表变量
declare @tb table(id int,namevarchar(50),age int)
insert @tb select 1,'nn',14 select * from @tb
--创建临时表
create table #t(id int,namevarchar(50),years int,numsint) insert #t select 1,'nn',14,15 union all select 1,'nn',14,15
insert into #t exec sp_gets --可以用于存储过程或动态SQL结合
select * from #t
drop table #t --删除临时表
实例
------------------------------------------------------------------
declare @tab table (
idint,
namenvarchar(50) )
insert into @tab(id,name)
select person_id,1 from personinfo select * from @tab
------------------------------------------------------------------
set ANSI_NULLS ON
set QUOTED_IDENTIFIER ON GO
-- =============================================
-- Author: -- Create date: <2012-07-04> -- Description: <获取家庭吸烟总量(创建表变量)> -- ============================================= ALTER PROCEDURE [dbo].[Family_SmokeTotal] (@Family_IDint) AS declare @tab table(Person_IDint) insert into @tab(Person_ID) selectPerson_ID from PersonInfo where Family_ID=@Family_ID select Sum(SmokeCount) '家庭吸烟总数' from PersonActionInfo where Person_id in (select Person_id from @tab) //临时表 CREATE TABLE #tmp ( rq NVARCHAR(10), shengfu NVARCHAR(1) ) INSERT into #tmp select'2005-05-09','胜' Insert into #tmp select'2005-05-09','胜' insert into #tmp select'2005-05-09','负' insert into #tmp select'2005-05-09','负' insert into #tmp select'2005-05-10','胜' insert into #tmp select'2005-05-10','负' insert into #tmp select'2005-05-10','负' SELECT rq,sum(case when shengfu='胜' then 1 else 0 end)'胜',sum(case when shengfu='负' then 1 else 0 end)'负' from #tmp group by rq drop table #tmp 因篇幅问题不能全部显示,请点此查看更多更全内容