mysql sum求和怎么采用
发布时间：2023-04-08 14:21:29 所属栏目：MySql教程 来源：
导读：本篇内容主要讲解“mysql sum求和怎么使用”，感兴趣的朋友不妨来看看。本文介绍的方法操作简单快捷，实用性强。下面就让小编来带大家学习“mysql sum求和怎么使用”吧!
mysql sum求和的方法
mysql sum求和的方法
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本篇内容主要讲解“mysql sum求和怎么使用”，感兴趣的朋友不妨来看看。本文介绍的方法操作简单快捷，实用性强。下面就让小编来带大家学习“mysql sum求和怎么使用”吧! mysql sum求和的方法：1、通过“select sum(value) as value from table where user_id”方式实现单一求和；2、通过嵌套语句多条件求和，语法如“(select sum(value) from table where type = 6 and type_son = 1) as xj0”。 一、单一的求和。 select sum(value) as value from table where user_id = 1 and type = 6 and type_son = 2 value 为求和的字段。 as 后面是 sum 求和后给它一个名称。 二、SQL语句中嵌套语句多条件求和。 select (select sum(value) from table where type = 6 and type_son = 1) as xj0, (select sum(value) from table where type = 6 and type_son = 2) as xj1, (select sum(value) from table where type = 3 and type_son = 3) as xj2, (select sum(value) from table where type = 4 and type_son = 3) as xj3 from table where user_id = 1 limit 0,1 as 后面是 sum 求和后给它一个名称，这样就不会冲突。 三、与第二个一样，但是不采取语句嵌套的方式求和，而是使用 sum 判断求和。 select sum(IF(type = 6 and type_son = 1,value,NULL)) as xj0, sum(IF(type = 6 and type_son = 2,value,NULL)) as xj1, sum(IF(type = 3 and type_son = 0,value,NULL)) as xj2, sum(IF(type = 4 and type_son = 3,value,NULL)) as xj3 from table where user_id = 1 sum(IF('条件判断'，'求和的字段'，'NULL不计算')) as '别名' 我觉得第三个的方式比前面两个的方式要好。 YII 2.0 使用 SUM 求和 $v['alls_bonus'] = AccountingLog::find() ->select([" sum( IF(type = 6 and type_son = 1,value,NULL) ) as xj0, sum( IF(type = 6 and type_son = 4,value,NULL) ) as xj1, sum( IF(type = 8 and type_son = 4,value,NULL) ) as xj2, sum( IF(type = 3 and type_son = 1,value,NULL) ) as xj3 "]) ->where(['user_id'=>1]) ->asArray() ->one(); 注意要在 select 里面加 ["sum........"]，否则会报错 （编辑：聊城站长网） 【声明】本站内容均来自网络，其相关言论仅代表作者个人观点，不代表本站立场。若无意侵犯到您的权利，请及时与联系站长删除相关内容! |
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