Why does SELECT results differ between mysql and sqlite?

Question

I\'m re-asking this question in a simplified and expanded manner.

Consider these sql statements:

create table foo (id INT, score INT);

insert into foo v         


        

Answer 1

I tried to mess with some variants of query.

It seems, like sqlite has errors in using of previous declared fields in a nested HAVING expressions.

In your example avg1 under second having is always equal to 5.0

Look:

select T1.id, avg(T1.score) avg1
from foo T1
group by T1.id
having not exists (
    SELECT 1 AS col1 GROUP BY col1 HAVING avg1 = 5.0);

This one returns nothing, but execution of the following query returns both records:

...
having not exists (
    SELECT 1 AS col1 GROUP BY col1 HAVING avg1 <> 5.0);

I can not find any similar bug at sqlite tickets list.