SQL2008同Oracle的Merge用法比较

以下测试环境 SQL 2008 同Oracle 10G
SQL2008:

USE tempdb;
GO
IF OBJECT_ID (N'Target', N'U') IS NOT NULL 
    DROP TABLE dbo.Target;
GO
Create table Target(ID int ,Name nvarchar(10))
insert into Target
values(1,'a'),(3,'b'),
(5,'c'),(10,'d')


GO
IF OBJECT_ID (N'dbo.Source', N'U') IS NOT NULL 
    DROP TABLE dbo.Source;
GO
Create table Source(ID int ,Name nvarchar(10))
insert into Source
values(2,'E'),(4,'F'),
(6,'H'),(10,'I')


/*Target--源表

ID	Name
1	a
3	b
5	c
10	d
*/

/*Source--目标表
ID	Name
2	E
4	F
6	H
10	I
*/

go
begin tran
merge Target as T
using Source as S
on (T.ID=S.ID)
when matched and T.Name<>S.Name					--ID相同，Name不同时更新
	then update set T.Name=S.Name
when not matched  then					--这里可不用写by Target(not matched by Target )没有的ID,新增
	insert (ID,Name)values(S.ID,S.Name)
when not matched by source then			--删除Target表在Source表没有的记录
	delete
OUTPUT $action, 
       inserted.ID AS SourceID, inserted.Name AS SourceName, 
       deleted.ID AS TargetID, deleted.Name AS TargetName;
       
select * from Target
select * from Source

rollback tran
/*$action
$action	SourceID	SourceName	TargetID	TargetName
INSERT	2	E	NULL	NULL
INSERT	4	F	NULL	NULL
INSERT	6	H	NULL	NULL
DELETE	NULL	NULL	1	a
DELETE	NULL	NULL	3	b
DELETE	NULL	NULL	5	c
UPDATE	10	I	10	d

Target
ID	Name
10	I
2	E
4	F
6	H

Source
ID	Name
2	E
4	F
6	H
10	I

*/
go

Oracle环境:

/**删除表
begin
execute immediate ' drop table Target';
exception when others then
null;
end;

begin
execute immediate ' drop table Source';
exception when others then
null;
end;
**/

Create table Target(ID int ,Name varchar2(10));
insert into Target values(1,'a');
insert into Target values(3,'b');
insert into Target values(5,'c');
insert into Target values(10,'d');

Create table Source(ID int ,Name varchar2(10));
insert into Source values(2,'E');
insert into Source values(4,'F');
insert into Source values(6,'H');
insert into Source values(10,'I');

/**Merge Into 语句代替Insert/Update**/
MERGE INTO Target  T   
 USING Source  S   
    ON (T.ID = S.ID)   
    WHEN MATCHED THEN  
    UPDATE  
     SET T.Name = S.Name
    WHERE T.Name<>S.Name 
    WHEN NOT MATCHED THEN  
     INSERT  
     VALUES (S.ID, S.Name);
     
/**删除不存在Source表记录**/
delete Target where not exists(select 1 from Source where ID=Target.ID);

/**--两表结果
Target/Source
ID	NAME
10	I
6	H
4	F
2	E
**/

原文链接： http://blog.csdn.net/roy_88/article/details/6942055