MERGE 更新和插入合并

 

MERGE INTO [target-table] A USING [source-table sql] B ON([conditional expression] and [...]...)
WHEN MATCHED THEN
    [UPDATE sql]
WHEN NOT MATCHED THEN
    [INSERT sql]

举例子：

MERGE INTO A t1
 
USING  (select count(*) c from A t2 where t2.key='key1' )x
ON (x.c > 0)
when matched then 
      update set t1.value='test', t1.version = sysdate where t1.key='key1
when not matched then 
      insert values('值1','值2','值3');