在Postgres中的hading子句中引用选择聚合列别名 [英] Referring to a select aggregate column alias in the having clause in Postgres

问题描述

我正在从MySQL迁移到Postgres.在MySQL中，我可以使用

I'm migrating from MySQL to Postgres. In MySQL I can use

select sum(clicks) c from table where event_date >= '1999-01-01' 
group by keyword_id 
having c > 10

Postgres给出了错误

Postgres gives an error

错误:列"c"不存在

ERROR: column "c" does not exist

在Postgres中，我必须在hading子句中重复该功能

In Postgres I have to repeat the function in the having clause

select sum(clicks) c from table where event_date >= '1999-01-01' 
group by keyword_id 
having sum(clicks) > 10

我必须在代码中更改很多地方.在Postgres中是否有一个设置可以允许它在hading子句中使用列别名?

There are a lot of places in the code that I have to change. Is there a setting in Postgres that will allow it to use column aliases in the having clause?

推荐答案

Postgres中是否有一个设置，允许它在hading子句中使用列别名?

Is there a setting in Postgres that will allow it to use column aliases in the having clause?

不.允许引用HAVING中的SELECT -list条目的实现超出了标准.

No. Implementations that allow references to SELECT-list entries in HAVING are going outside the standard.

您应该使用子查询，例如

You should use a subquery, e.g.

select
  c
from (
  select 
    sum(clicks) c
  from table
  where event_date >= '1999-01-01'
  group by keyword_id 
) x
where c > 10;

...或重复汇总.

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