sql - "column must appear in the GROUP BY clause or be used in an aggregate function"

Question

我在 postgresql 中有这个查询，我期望的是一个包含两列的表。一个叫counter，另一个叫forn_primario。 但相反，我收到此错误:“列“forn_primario”必须出现在 GROUP BY 子句中或用于聚合函数中”

Select MAX(contador) as counter, forn_primario
From(
Select COUNT(DISTINCT categoria) as contador, forn_primario
From produto
Group by forn_primario)t

也在这个查询之后

Select COUNT(DISTINCT categoria) as contador, forn_primario
From produto
Group by forn_primario

我得到了这张表

 contador | forn_primario 
----------+---------------
        1 | 103246782
       17 | 113056729
        2 | 120456781
        3 | 123456719
        1 | 133956139
        2 | 143856248
        2 | 153756357
        1 | 163656466
        2 | 173516575
        1 | 183426684
        1 | 193336793

在主查询之后我应该有这张表:

  counter | forn_primario 
----------+---------------
       17 | 113056729

Answer 1

我想你想要这个:

Select COUNT(DISTINCT categoria) as contador, forn_primario
From produto
Group by forn_primario
Order by contador DESC
Limit 1;