如何使用MERGE的SQL语句来插入新的价值

Question

我有2个表：

A: 
---------- 
Key | Value | PK_A 


B: 
----------- 
Key | Value 

如何插入新的（键，值）表A从表B，其仅在表B中。我尝试过使用MERGE，但我不确定如何使用新的主键PK_A

MERGE INTO A 
USING (SELECT key, value FROM B) 
ON (A.Key = B.key AND A.value = B.value) 
WHEN NOT MATCHED THEN INSERT (D.key, D.value, ???) VALUES (B.key, B.value, ???); 

Answer 1

创建一个序列来填充PK_A。

CREATE SEQUENCE PK_A_SEQ; 

然后，

MERGE INTO A 
USING (SELECT key, value FROM B) 
ON (A.Key = B.key AND A.value = B.value) 
WHEN NOT MATCHED THEN INSERT (D.key, D.value, D.PK_A) VALUES (B.key, B.value, PK_A_SEQ.NEXTVAL);