oracle merge

1 MERGE 语法:

MERGE INTO [your table-name] [rename your table here] 
USING ( [write your query here] )[rename your query-sql and using just like a table] 
ON ([conditional expression here] AND [...]...) 
WHEN MATCHED THEN [here you can execute some update sql or something else ] 
WHEN NOT MATCHED THEN [execute something else here ! ] 

2 使用例子：

MERGE INTO dept60_bonuses b
USING (
           SELECT employee_id, salary, department_id
           FROM hr.employees
           WHERE department_id = 60
      ) e
ON (b.employee_id = e.employee_id)
-- 当符合关联条件时
WHEN MATCHED THEN
     -- 将奖金为0的员工的奖金调整为其工资的20%
     UPDATE
     SET b.bonus_amt = e.salary * 0.2
     WHERE b.bonus_amt = 0
     -- 删除工资大于7500的员工奖金记录
     DELETE
     WHERE (e.salary > 7500)
-- 当不符合连接条件时
WHEN NOT MATCHED THEN
     -- 将不在部门为60号的，且不在dept60_bonuses表的用工信息插入，并将其奖金设置为其工资的10%
     INSERT
     (b.employee_id, b.bonus_amt)
     VALUES
     (e.employee_id, e.salary * 0.1)
     WHERE (e.salary < 7500)
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原文链接：https://blog.youkuaiyun.com/zorro_jin/article/details/81053693