separate WHERE & HAVING in expression result & fix buggy having rewrite

[hrach]

[closes #666]

[stepapo]

I am a bit confused with separate WHERE and HAVING in some cases. For example these two produce identical query, which can't be right, as it only works with AND.

$this->model->books->findBy([
    ICollection::OR,
    ['title' => 'Book 1'],
    [CompareGreaterThanFunction::class, [CountAggregateFunction::class, 'tags->id'], 0],
]);
$this->model->books->findBy([
    ICollection::AND,
    ['title' => 'Book 1'],
    [CompareGreaterThanFunction::class, [CountAggregateFunction::class, 'tags->id'], 0],
]);

SELECT "books".* FROM "books" AS "books" 
LEFT JOIN "books_x_tags" AS "books_x_tags__COUNT" ON ("books"."id" = "books_x_tags__COUNT"."book_id") 
LEFT JOIN "tags" AS "tags__COUNT" ON ("books_x_tags__COUNT"."tag_id" = "tags__COUNT"."id") 
WHERE ((("books"."title" = 'Book 1'))) 
GROUP BY "books"."id", "books"."title" 
HAVING ((COUNT("tags__COUNT"."id") > 0));

[hrach]

@stepapo thx for testcases, did you test them on the #687? Yeah, with #687 I'm thinking about reverting this.

[stepapo]

@stepapo thx for testcases, did you test them on the #687? Yeah, with #687 I'm thinking about reverting this.

Yes I tested them on #687 .