函数写法
```
CREATE PROCEDURE test ()
BEGIN
UPDATE `sgo_want_orders` SET audit=20
WHERE unix_timestamp(now()-interval 900 second) > create_time
and audit=1
and type <> 1 ;
END
```
创建事件
```
create event if not exists e_test
on schedule every 30 second
on completion preserve
do call test();
```
