如何使用MERGE SQL-Statement插入新值

Question

我有两张桌子：

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


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

如何在表B中的表A中插入新的（键，值），仅在表B中。我试过使用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);