ATLChris ATLChris - 8 days ago 5
PHP Question

Does anyone know how to use "group by" with a polymorphic relationship in Laravel?

I have the following relationship:

return $this->morphedByMany('App\Models\Movie', 'listable', 'cnt_lists', 'list_id')->withPivot('id', 'order', 'updated_at')->where('movies.has_poster', true)->orderBy('order', 'desc')->withTimestamps();


That relationship produces this query:

select `movies`.*, `cnt_lists`.`list_id` as `pivot_list_id`, `cnt_lists`.`listable_id` as `pivot_listable_id`, `cnt_lists`.`id` as `pivot_id`, `cnt_lists`.`order` as `pivot_order`, `cnt_lists`.`updated_at` as `pivot_updated_at`, `cnt_lists`.`created_at` as `pivot_created_at` from `movies` inner join `cnt_lists` on `movies`.`id` = `cnt_lists`.`listable_id` where `movies`.`has_poster` = '1' and `cnt_lists`.`list_id` in ('3176', '3283', '3285', '3287') and `cnt_lists`.`listable_type` = 'App\Models\Movie' order by `order` desc


This relationship works, but it grabs many for each list. I am trying to limit to just one per list. I was originally exploring
take()
but that limits the whole result set, not a per list limit. I then thought I could group by the
cnt_lists.list_id
which would grab one per list. This seems to get me what I am looking for. Below is the query that works for me, I am just trying to figure out how to use group by in the relationship because it breaks the relationship when I add it.

select `movies`.*, `cnt_lists`.`list_id` as `pivot_list_id`, `cnt_lists`.`listable_id` as `pivot_listable_id`, `cnt_lists`.`id` as `pivot_id`, `cnt_lists`.`order` as `pivot_order`, `cnt_lists`.`updated_at` as `pivot_updated_at`, `cnt_lists`.`created_at` as `pivot_created_at` from `movies` inner join `cnt_lists` on `movies`.`id` = `cnt_lists`.`listable_id` where `movies`.`has_poster` = '1' and `cnt_lists`.`list_id` in ('3176', '3283', '3285', '3287') and `cnt_lists`.`listable_type` = 'App\Models\Movie' group by `cnt_lists`.`list_id` order by `order` desc


When I add
groupBy
in the relationship:

return $this->morphedByMany('App\Models\Movie', 'listable', 'cnt_lists', 'list_id')->withPivot('id', 'order', 'updated_at')->where('movies.has_poster', true)->groupBy('cnt_lists.list_id')->orderBy('order', 'desc')->withTimestamps();


I get the following error:

select `movies`.*, `cnt_lists`.`list_id` as `pivot_list_id`, `cnt_lists`.`listable_id` as `pivot_listable_id`, `cnt_lists`.`id` as `pivot_id`, `cnt_lists`.`order` as `pivot_order`, `cnt_lists`.`updated_at` as `pivot_updated_at`, `cnt_lists`.`created_at` as `pivot_created_at` from `movies` inner join `cnt_lists` on `movies`.`id` = `cnt_lists`.`listable_id` where `movies`.`has_poster` = 1 and `cnt_lists`.`list_id` in (3176, 3283, 3285, 3287) and `cnt_lists`.`listable_type` = App\Models\Movie group by `cnt_lists`.`list_id` order by `order` desc


For some reason, the model
App\Models\Movie
is not in quotes so it breaks the whole query. If I run the query manually it works, I just have to add quotes to the polymorphic model. i.e.
"App\Models\Movie"

Answer

Ok, so it turns out that the issue was related to MySQL strict mode, which includes ONLY_FULL_GROUP_BY mode.

I disabled strict mode at the Laravel level and the query is now working as expected. Just set to strict to false in the database config file for your connection.

'strict' => false,