Question

Select rating_id, average_rating

From (Select rating_id, avg(rating_num) as average_rating
    from ratings
    group by rating_id
    having count(*) > 50)

HAVING average_rating > 4 ;

After running the query, I get an error

Every derived table must have its own alias

I know that the section here works:

Select rating_id, avg(rating_num) as average_rating
        from ratings
        group by rating_id
        having count(*) > 50

What am I doing wrong in this subquery? I searched and searched and searched but couldn’t find the mistake, no matter where I corrected, I still get errors

Answer 1

Put “as SomeAlias” after the subquery:

Select rating_id, average_rating

From (Select rating_id, avg(rating_num) as average_rating
    from ratings
    group by rating_id
    having count(*) > 50) as A

HAVING average_rating > 4 ;