Oracle中Merge的使用

MERGE INTO products p
USING product_changes pc
ON (p.product_id = pc.product_id)
WHEN MATCHED THEN  --当匹配上时进行更新操作
  UPDATE
     SET p.product_type_id = pc.product_type_id,
         p.name            = pc.name,
         p.description     = pc.description,
         p.price           = pc.price
WHEN NOT MATCHED THEN  --当不匹配上时进行插入操作
  INSERT
    (p.product_id, p.product_type_id, p.name, p.description, p.price)
  VALUES
    (pc.product_id, pc.product_type_id, pc.name, pc.description, pc.price);