merge into 的用法

已创建 1 行。

 

SQL> commit;

 

----不带where子句

SQL>  merge into merge1

  2     using merge2

  3   on (merge1.id = merge2.id)

  4   when matched then

  5     update

  6    set merge1.name = merge2.name;

 

3 行已合并。

 

SQL> rollback;

 

回退已完成。

 

---带where子句

SQL>   merge into merge1 a

  2    using merge2 b

  3   on (a.id = b.id)

  4   when matched then

  5    update

  6    set a.name = b.name

  7   where a.name <> b.name;

 

0 行已合并。

 

------如果要更新b表，这样写会出错

SQL>    merge into merge1 a

  2     using merge2 b

  3    on (a.id = b.id)

  4    when matched then

  5     update

  6     set b.name = a.name;

   set b.name = a.name

       *

第 6 行出现错误:

ORA-00904: "B"."NAME": 标识符无效

----------------------------------------

;MERGE INTO Loanee p
USING ( SELECT * FROM @TApply AS nc) c on p.ApplicationID=c.ApplicationID
WHEN MATCHED THEN UPDATE set p.UpdateTime=getdate()
WHEN NOT MATCHED BY TARGET THEN INSERT
(
LoaneeNumber,LoaneeName,LoanDate,LockMatchRatio,SurplusMatchRatio,
MatchRatio,MatchAmount,LockAmount,LoaneeAmount,ExpectedYield,
LoanPeriod,CreditRating,FreeState,UpdateTime,AddTime,
DeleteState,IsFullState,FullTime,LoaneeType,ApplicationID,
CashAccountNo,ContractTime,RelaseRatio,MatchOrder,KsshDate,
LockState,CashAccountNo_Name,loaneeSource,Broker_CashAccount,Broker_CashAccountName,ApprovalTime)
VALUES(
c.LoaneeNumber,c.[LoaneeName],c.[LoanDate],0,1,
0,0,0,c.[LoaneeAmount],c.[ExpectedYield],
c.[LoanPeriod],c.[CreditRating],0,getdate(),getdate(),
0,0,null,0,c.[ApplicationID],
c.[CashAccountNo],c.[ContractTime],0,c.[MatchOrder],[KsshDate],
0,c.[CashAccountNo_Name],0,c.[Broker_CashAccount],c.[Broker_CashAccountName],c.ApprovalTime
);

以上例子的作用就是，向一个表中插入数据时，判断是否存在，不存在则插入，存在则更新