Question

使用此条件复制表另一个表

如果旧表中的记录是新副本它到新表
如果旧表中的记录已更改且该记录存在于新表中表更新记录新表中的信息

Answer 1

对你要做的事做一些大的假设，但是......如果我猜对了，这应该会让你接近：

Insert Into New_Table
Select  *
From    Old_Table
Where   NOT EXISTS ( Select * from New_Table )

Update New_Table NT
From     Old_Table OT
Where   NT.PK = OT.PK
   and    ( NT.attrib_fld_1   <>   OT.atrib_fld_1
    OR
     NT.attrib_fld_1   <>   OT.atrib_fld_1
    OR
     NT.attrib_fld_1   <>   OT.atrib_fld_1
    OR
     NT.attrib_fld_1   <>   OT.atrib_fld_1
    -- etc..for as many non key fields as need evaluated 
    )

Answer 2

＆＃13;

--Here is an example with merge statement

USE tempdb;
GO

CREATE TABLE dbo.NewTable(EmployeeID int, EmployeeName varchar(10), 
     CONSTRAINT NewTable_PK PRIMARY KEY(EmployeeID));
CREATE TABLE dbo.OldTable(EmployeeID int, EmployeeName varchar(10), 
     CONSTRAINT OldTable_PK PRIMARY KEY(EmployeeID));
GO
INSERT dbo.NewTable(EmployeeID, EmployeeName) VALUES(100, 'Mary');
INSERT dbo.NewTable(EmployeeID, EmployeeName) VALUES(101, 'Sara');
INSERT dbo.NewTable(EmployeeID, EmployeeName) VALUES(102, 'Stefano');
INSERT dbo.NewTable(EmployeeID, EmployeeName) Values(103, 'John');

GO
INSERT dbo.OldTable(EmployeeID, EmployeeName) Values(103, 'Bob');
INSERT dbo.OldTable(EmployeeID, EmployeeName) Values(104, 'Steve');

GO

USE tempdb;
GO
BEGIN TRAN;
MERGE [NewTable] AS T
USING [OldTable] AS S
ON (T.EmployeeID = S.EmployeeID) 
WHEN NOT MATCHED BY TARGET 
    THEN INSERT(EmployeeID, EmployeeName) VALUES(S.EmployeeID, S.EmployeeName)
WHEN MATCHED 
    THEN UPDATE SET T.EmployeeName = S.EmployeeName

OUTPUT $action, inserted.*, deleted.*;

IF @@ERROR <> 0
 ROLLBACK TRAN; 
ELSE
 COMMIT TRAN;
GO

＆＃13;

使用此条件将表复制到另一个表

2 个答案: