Oracle-merge语句学习

1.语法格式

MERGE <hint> 

INTO <table_name> 

USING <table_view_or_query> 

ON (<condition>) 

WHEN MATCHED THEN <update_clause> 

DELETE <where_clause> 

WHEN NOT MATCHED THEN <insert_clause> 

[LOG ERRORS <log_errors_clause> <reject limit <integer | unlimited>];

2.测试数据

create table dept_bonuses
(employee_id	number,
bonus_amt		number);

insert into dept_bonuses values(103,0);
insert into dept_bonuses values(104,100);
insert into dept_bonuses values(105,0);

commit;

create table employees
(employee_id	number,
department_id  number,
last_name		varchar2(20),
salary			number);

insert into employees values(103,60,'A',9000);
insert into employees values(104,60,'B',6000);
insert into employees values(105,60,'C',4800);
insert into employees values(106,60,'D',9800);
insert into employees values(107,60,'E',4200);

commit;

kin@KIN>select * from dept_bonuses;

EMPLOYEE_ID  BONUS_AMT
----------- ----------
103	     0
104	   100
105	     0

kin@KIN>select * from employees;

EMPLOYEE_ID DEPARTMENT_ID LAST_NAME		   SALARY
----------- ------------- -------------------- ----------
103	       60 A			     9000
104	       60 B			     6000
105	       60 C			     4800
106	       60 D			     9800

3.测试merge语句

merge into dept_bonuses b
using (
select employee_id,salary,department_id
from employees
where department_id = 60) e
on (b.employee_id = e.employee_id)
when matched then
update set b.bonus_amt = e.salary * 0.2
where b.bonus_amt = 0
delete where (e.salary > 7500)
when not matched then
insert (b.employee_id,b.bonus_amt)
values (e.employee_id,e.salary * 0.1)
where  (e.salary < 7500);

kin@KIN>select * from dept_bonuses;

EMPLOYEE_ID  BONUS_AMT
----------- ----------
104	   100
105	   960
107	   420