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mysql iF语句

mysql手册中如是说: IF(expr1,expr2,expr3) 如果 expr1 为真(expr1 0 以及 expr1 NULL),那么 IF() 返回 expr2,否则返回 expr3。IF() 返回一个数字或字符串,这取决于它被使用的语境: mysql> SELECT IF(1>2,2,3); -> 3 mysql> SELECT IF(1 'y...

如果是存储过程: insert into 这句后面应该添加 ; 如果是SQL语句,IF的用法完全不是这样的: 例子:select if(2>0,"正确","错误") from tab1; 楼主的目的是啥不清楚,可以参考如下的例子: insert into tab1 values( if(2>0,'aaaa','bbbb'));

left join没有关联到的都会置成NULL, 跟你ifnull没有关系 写在最外层才有效果,像这样 SELECT a.*, ifnull(c.order_number,0) from `table_a` as a left join (select partner_id, IFNULL(count(order_id),0) as order_number from `table_c` g...

mysql的case 就是 类似switch的用法, SELECT id,case status WHEN '0' then '审核中' WHEN '1' then '通过' WHEN '3' then '禁用' end as "status" from tp_user if的用法: select *,if(sex=1,"男","女") as sex from tp_user

select *,if(sva=1,"男","女") as ssva from tableame where id =1 Quote 控制流程函数 CASE value WHEN [compare-value] THEN result [WHEN [compare-value] THEN result ...] [ELSE result] END CASE WHEN [condition] THEN result [WHEN [con...

--在5.1.55中运行没问题--另外没有show version,只有select version();--你拷贝下面的代码试试?create procedure `test2`(IN cusername VARCHAR(50),IN cpassword VARCHAR(50),IN clastloginio VARCHAR(50))BEGINif exists(select * from mt_u...

mysql中没有if可以使用case when then end 来代替; 例如:查询语句select case 字段 when 1 then '一' when 2 then '二' end from 表名;

应该这样写吧: SELECT COUNT(*) FROM tougao_record WHERE accept_company_id=100 AND channel_type=1 AND check_status=6

写入“select * from pre_common_block_item where bid = 4 and case when panduanziduan!=0 then panduanziduan

select中的IF函数是if(A=B,0,other) IF语句 if a=b then 0; else 1; end if;

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