How to Eager Loading Specific Columns for Polymorphic relation?

[siarheipashkevich]

https://laravel.com/docs/11.x/eloquent-relationships#eager-loading-specific-columns

Is anybody trying to specify columns for polymorphic relations?

'items.item' => function (MorphTo $morphTo) {
    // It's needed for determining the item is weight or not by unit.
    $morphTo->morphWith([
        Product::class => ['unit'], // <<< but, how to include only id and name columns for product model?
        Ingredient::class => ['unit'], // <<< but, how to include only id and name columns for ingredient model?
    ]);
},

[GhostvOne]

You can use contraint : https://laravel.com/docs/10.x/eloquent-relationships#constraining-eager-loading-of-morph-to-relationships

[mankowitz]

This did not work for me.

    $banners = Banner::with(['bannerable' => function (MorphTo $morphTo) {
      $morphTo->constrain([
        Agency::class => fn($q) => $q->select(['id', 'title'])->orderBy('title'),
        Site::class => fn($q) => $q->select(['id', 'name'])->orderBy('name'),
      ]);
    }])->get();

In each case, the full Agency and Site records were retrieved.

[macropay-solutions]

For non morph relations this works:

$builder->with('rel', function(Relation|Builder $query): void {
    $query->select(['col']);
});

You can try:
@mankowitz

    $banners = Banner::with(['bannerable' => function (MorphTo $morphTo) {
      $morphTo->constrain([
        Agency::class => fn($q) => $q->select(['id', 'title'])->orderBy('title'),
        Site::class => fn($q) => $q->select(['id', 'name'])->orderBy('name'),
      ])->select(['id', 'name']); // maybe you have to qualify the selected columns.
    }])->get();

or
@siarheipashkevich

'items.item' => function (MorphTo $morphTo) {
    // It's needed for determining the item is weight or not by unit.
    $morphTo->morphWith([
        Product::class => ['unit'], // <<< but, how to include only id and name columns for product model?
        Ingredient::class => ['unit'], // <<< but, how to include only id and name columns for ingredient model?
    ])->select(['id', 'name']); // maybe you have to qualify the selected columns.
},

Bear in mind that you NEED to get the column that links the relation to the model for the eager loading to match the relation row with the model.