SQLServer 2008中SQL增强之三 Merge(在一条语句中使用

if OBJECT_ID('Demo_AllProducts') is not null
drop table Demo_AllProducts
go
Create table Demo_AllProducts
(PKID int not null identity(1,1) primary key
,DName Nvarchar(20) null
,DCode NVarchar(30) null
,DDate datetime null
)
go

--this SQL is only for SQL Server 2008
Insert into Demo_AllProducts
(DName,DCode,DDate)
values
('DemoA','AAA',GETDATE()),
('DemoB','BBB',GETDATE()),
('DemoC','CCC',GETDATE()),
('DemoD','DDD',GETDATE()),
('DemoE','EEE',GETDATE())

select from Demo_AllProducts

--PKID DName DCode DDate
--1 DemoA AAA 2010-10-12 20:33:54.417
--2 DemoB BBB 2010-10-12 20:33:54.417
--3 DemoC CCC 2010-10-12 20:33:54.417
--4 DemoD DDD 2010-10-12 20:33:54.417
--5 DemoE EEE 2010-10-12 20:33:54.417

if OBJECT_ID('Demo_Shop1_Product') is not null
drop table Demo_Shop1_Product
go

Create table Demo_Shop1_Product
(PKID int not null identity(1,1) primary key
,DName Nvarchar(20) null
,DCode NVarchar(30) null
,DDate datetime null
)
go

--this SQL is only for SQL Server 2008
Insert into Demo_Shop1_Product
(DName,DCode,DDate)
values
('DemoA','AAA',GETDATE()),
('DemoB','CCC',GETDATE()),
('DemoF','FFF',GETDATE())

select from Demo_Shop1_Product

--PKID DName DCode DDate
--1 DemoA AAA 2010-10-17 20:19:32.767
--2 DemoB CCC 2010-10-17 20:19:32.767
--3 DemoF FFF 2010-10-17 20:19:32.767

--确定目标表
Merge Into Demo_AllProducts p
--从数据源查找编码相同的产品
using Demo_Shop1_Product s on p.DCode=s.DCode
--如果编码相同，则更新目标表的名称
When Matched and P.DName<>s.DName Then Update set P.DName=s.DName
--如果目标表中不存在，则从数据源插入目标表
When Not Matched By Target Then Insert (DName,DCode,DDate) values (s.DName,s.DCode,s.DDate)
--如果数据源的行在源表中不存在，则删除源表行
When Not Matched By Source Then Delete;

--PKID DName DCode DDate
--1 DemoA AAA 2010-10-17 20:31:00.827
--2 DemoB CCC 2010-10-17 20:31:00.827
--3 DemoF FFF 2010-10-17 20:31:00.827

--确定目标表
Merge Into Demo_AllProducts p
--从数据源查找编码相同的产品
using Demo_Shop1_Product s on p.DCode=s.DCode
--如果编码相同，则更新目标表的名称
When Matched and P.DName<>s.DName Then Update set P.DName=s.DName
--如果目标表中不存在，则从数据源插入目标表
When Not Matched By Target Then Insert (DName,DCode,DDate) values (s.DName,s.DCode,s.DDate);

--PKID DName DCode DDate
--1 DemoA AAA 2010-10-17 20:30:28.350
--2 DemoB BBB 2010-10-17 20:30:28.350
--3 DemoB CCC 2010-10-17 20:30:28.350
--4 DemoD DDD 2010-10-17 20:30:28.350
--5 DemoE EEE 2010-10-17 20:30:28.350
--6 DemoF FFF 2010-10-17 20:31:00.827

--PKID DName DCode DDate
--1 DemoA AAA 2010-10-17 20:31:00.827
--2 DemoB CCC 2010-10-17 20:31:00.827
--3 DemoF FFF 2010-10-17 20:31:00.827

--定义表变量以存储输出
Declare @tableVarRecord Table
(MPKID int not null identity(1,1) primary key
,PKID int null
,DName Nvarchar(20) null
,DCode NVarchar(30) null
,DDate datetime null
)

--确定目标表
Merge Into Demo_AllProducts p
--从数据源查找编码相同的产品
using Demo_Shop1_Product s on p.DCode=s.DCode
--如果编码相同，则更新目标表的名称
When Matched and P.DName<>s.DName Then
Update set P.DName=s.DName

--如果目标表中不存在，则从数据源插入目标表
When Not Matched By Target Then
Insert (DName,DCode,DDate) values (s.DName,s.DCode,s.DDate)

--如果数据源的行在源表中不存在，则删除源表行
When Not Matched By Source Then
Delete OUTPUT deleted. INTO @tableVarRecord;
----Delete OUTPUT Inserted. INTO @tableVarRecord;

--返回上个Merge语句影响的行数
select @@ROWCOUNT as Count1,ROWCOUNT_BIG() as Count2

select from @tableVarRecord;

--影响的行数
--Count1 Count2
--5 5

--Deleted表的行
--MPKID PKID DName DCode DDate
--1 NULL NULL NULL NULL
--2 2 DemoB BBB 2010-10-17 21:42:30.700
--3 3 DemoC CCC 2010-10-17 21:42:30.700
--4 4 DemoD DDD 2010-10-17 21:42:30.700
--5 5 DemoE EEE 2010-10-17 21:42:30.700