# Why doesn't my query deliver singular results?

**URL:** <https://www.ruby-forum.com/t/why-doesnt-my-query-deliver-singular-results/258902>\
**Category:** Uncategorized\
**Created:** [March 17, 2020, 9:15am UTC](https://www.ruby-forum.com/t/why-doesnt-my-query-deliver-singular-results/258902 "2020-03-17T09:15:09Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![von\_spotz](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/v/e19adc/32.png) [@von\_spotz](https://www.ruby-forum.com/u/von_spotz)\
**Post date:** [March 17, 2020, 9:15am UTC](https://www.ruby-forum.com/t/why-doesnt-my-query-deliver-singular-results/258902/1 "2020-03-17T09:15:10Z")

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Hello,

I have following query with `group by` and `having` plus `count`. It should return only those entries specified in the `group by` clause as they have `count`.

`@articles = Article.joins(:taggings).where(taggings: { tag_id: @article_tags_ids, taggable_type: "Article"}).group('articles.id').having("count(taggings.tag_id) = ?", @article_tags_count)`

The models behind this are from here [https://cobwwweb.com/rails-has-many-through-polymorphic-association](https://cobwwweb.com/rails-has-many-through-polymorphic-association)

It shall only and exactly return articles with the tags the user searches for. It shall decidedly not return those articles that have the tags the user searched for plus others.

Although the groub().having(“count…”) defining the number of permissable tag-entries it does return latter article-entries with tags-searched-for-plus-others.

Yours sincerely

von Spotz

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**Author:** ![pjscopeland](https://www.ruby-forum.com/user_avatar/www.ruby-forum.com/pjscopeland/32/2362_2.png) [@pjscopeland](https://www.ruby-forum.com/u/pjscopeland)\
**Post date:** [March 19, 2020, 9:43pm UTC](https://www.ruby-forum.com/t/why-doesnt-my-query-deliver-singular-results/258902/2 "2020-03-19T21:43:23Z")

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Some more information would be helpful. What’s in `@article_tags_ids` and `@article_tags_count`? Where do they come from? _Exactly_ what results are you (1) expecting to get, (2) expecting _not_ to get, and (3) actually getting?

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<div class="post-metadata">

**Author:** ![von\_spotz](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/v/e19adc/32.png) [@von\_spotz](https://www.ruby-forum.com/u/von_spotz)\
**Post date:** [March 21, 2020, 6:40am UTC](https://www.ruby-forum.com/t/why-doesnt-my-query-deliver-singular-results/258902/3 "2020-03-21T06:40:42Z")

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Hello pjscopeland,

`@article_tags_ids` are the ids of the tags searched for  
`@article_tags_count` is their count for the `having count`-clause.

The generated SQL query is

```
SELECT
  `articles`.* 
FROM
  `articles` 
INNER JOIN `taggings` 
  ON `taggings`.`taggable_id` = `articles`.`id` 
  AND `taggings`.`taggable_type` = 'Article' 
WHERE
  `taggings`.`tag_id` IN (1, 3) 
  AND `taggings`.`taggable_type` = 'Article' 
GROUP BY
  articles.id 
HAVING
  (count(taggings.tag_id) = 2) 
LIMIT 11

```

As I said. What I expected would be that the result sets only contains the articles tagged with exactly the tags with the ids of 1 and 3, e.g. [1,3] but not decidedly not [1,3,5] or [1,2,3]. What I am frustratetingly getting however is the latter. The result set also contains the articles who have tags just `IN(1,3)` but over that do also have other tags.

Yours sincerly

von Spotz

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<div class="post-metadata">

**Author:** ![von\_spotz](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/v/e19adc/32.png) [@von\_spotz](https://www.ruby-forum.com/u/von_spotz)\
**Post date:** [March 27, 2020, 5:13am UTC](https://www.ruby-forum.com/t/why-doesnt-my-query-deliver-singular-results/258902/4 "2020-03-27T05:13:24Z")

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Does noone have an idea why the count of `tag_id` isn’t applied to articles.ids ?