I have products table This products table has many 'product_images' items.
1 product -> many images.
If i use \Model_Products::find('all'); I can loop image in the product list page.
But, if i use \Model_Products::query()->related('product_images')->where('...conditions...')->get(); I can still list products but cannot loop image in product list. The image show only one.
Model _has_many and _belongs_to was set correctly. (because it works with find('all') but not with query()->related();)
If you do a find('all') like that, the ORM will use lazy loading to get the related information when you request it. That means in your loop it will fire a new query for every product to get the images.
When you use 'related' (you can do that in a find 'all' too) you switch to eager loading, and the ORM will generate a JOIN query to get all data, which in most cases is more efficient.
Both queries should give you the same output, so I can't say what the cause is, I have never seen this.
Enable the DB profiler, and check what SQL is generated for that query, and see if you can spot something odd?
No, absolutely not. A group_by will destroy the result, you need the individual child records.
So if you have 1 product and 4 related image records, the JOIN should produce 4 records (in which the product part is repeated), the ORM's hydration logic will split that result back into 1 product object and 4 related image objects.
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