PostgreSQL错误中WHERE子句中不允许的聚合 [英] Aggregates not allowed in WHERE clause in postgreSQL error

问题描述

我正在尝试执行以下查询，并且我是编写 SQL 查询的初学者，想知道如何在<$中执行以下聚合函数功能c $ c> WHERE 子句。对我来说，任何帮助都是一条很好的学习曲线。

I was trying to execute this following query, and I am a beginner in writing SQL Queries, was wondering how can I achieve the following aggregate functions functionality doing in WHERE clause. Any help on this would be a great learning curve for me.

 select a.name,a.add,a.mobile from user a
     INNER JOIN user_info aac
        ON aac.userid= a.userid  
     INNER JOIN info ac 
        ON aac.infoid= ac.infoid  
    WHERE a.total < 8* AVG(ac.total) 
 GROUP BY a.name, a.add, a.mobile;

这是我在PostgreSQL中遇到的错误：

And this is the error I am getting in PostgreSQL:

ERROR:  aggregates not allowed in WHERE clause
LINE 1: ...infoid = ac.infoid where a.total < 8* AVG(ac.tot...
                                                             ^

********** Error **********

ERROR: aggregates not allowed in WHERE clause
SQL state: 42803
Character: 190

我想使用 Having 子句获得结果吗？对此进行任何更正都会有很大帮助！

Am I suppose to use Having clause to have the results? any correction on this would be a great help!

推荐答案

您可以在子查询中使用窗口函数来做到这一点：

You can do this with a window function in a subquery:

select name, add, mobile
from (select a.name, a.add, a.mobile, total,
             avg(ac.total) over (partition by a.name, a.add, a.mobile) as avgtotal, a.total
      from user a INNER JOIN
           user_info aac
           ON aac.userid= a.userid INNER JOIN
           info ac 
           ON aac.infoid= ac.infoid
     ) t
WHERE total < 8 * avgtotal
GROUP BY name, add, mobile;

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