group by 子句

zzz大王

于 2025-02-21 17:26:29 发布

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文章标签：数据库

本文链接：https://blog.youkuaiyun.com/zzzbigkong/article/details/145782104

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SELECT 
   date,
   SUM(p.amount) AS total_amount,
   name AS payment_method
FROM payments p
JOIN payment_methods pm
   ON p.payment_method = pm.payment_method_id 
 GROUP BY date, payment_method

最开始我们讲述方程式，有SUM MAX MIN 等，延续到SUM 的多种运用，但是这个是总列的加总，所以我们加上了条件，针对于‘同一名字’‘同一地点’‘同一编号’的加总。

所以引入了group by子句，这里是利用date和payment_method作为条件

需要注意的是，多个条件之间用逗号连接，而不是AND 连接，会报错，报错

Error Code: 1055. Expression #1 of SELECT list is not in GROUP BY clause and contains nonaggregated column 'sql_invoicing.p.date' which is not functionally dependent on columns in GROUP BY clause; this is incompatible with sql_mode=only_full_group_by 0.000 sec