mysql - 为什么我的触发器不起作用？

Question

我的触发器：

create trigger cnt after insert on tc_contract
  for each rowbegin
    select count(*) into @num from tc_contract group by account_id where account_id = new.account_id;
    if @num >0 and @num <3 then
      update tc_account set account_status = 2 where account_id = new.account_id;
    end if;
end    

错误信息：

You have an error in your SQL syntax; check the manual that corresponds to your MySQL 
server version for the right syntax to use near 'where account_id = new.account_id;
if @num >0 and @num <3 then update tc_accou' at line 4

Answer 1

您需要将子句放在WHERE子句之前GROUP BY。

IE

select count(*)
into @num
from tc_contract
where account_id = new.account_id
group by account_id;