Yii Relations. How to select properly unique values ​​from related table?

Question

MySQL

Good afternoon
There are 2 tables:
Product entities (reduced, there are more fields):

CREATE TABLE `goods` (
  `id` INT(10) UNSIGNED NOT NULL AUTO_INCREMENT,
  `menutitle` VARCHAR(250) NOT NULL COMMENT 'Название',
  PRIMARY KEY (`id`),
  INDEX `menutitle` (`menutitle`),
  INDEX `FK_goods_goods_brand` (`brand_id`),
  CONSTRAINT `FK_goods_goods_brand` FOREIGN KEY (`brand_id`) REFERENCES `goods_brand` (`id`)
)
COLLATE='utf8_general_ci'
ENGINE=InnoDB
AUTO_INCREMENT=3782;

Possible variations of the product (EAV decided to bypass for now):

CREATE TABLE `goods_variations` (
  `id` INT(10) UNSIGNED NOT NULL AUTO_INCREMENT,
  `goods_id` INT(10) UNSIGNED NOT NULL,
  `articul` VARCHAR(100) NULL DEFAULT NULL,
  `size` VARCHAR(100) NULL DEFAULT NULL,
  `color` VARCHAR(100) NULL DEFAULT NULL,
  `weight` VARCHAR(100) NULL DEFAULT NULL,
  `stock` INT(5) NULL DEFAULT NULL,
  PRIMARY KEY (`id`),
  INDEX `FK_goods_options_goods` (`goods_id`),
  INDEX `articul` (`articul`),
  CONSTRAINT `FK_goods_options_goods` FOREIGN KEY (`goods_id`) REFERENCES `goods` (`id`)
)
COLLATE='utf8_general_ci'
ENGINE=InnoDB
AUTO_INCREMENT=5060;

Links in models:
Goods model (entities of goods, table 1).

'variations' => array(self::HAS_MANY, 'GoodsVariations', 'goods_id'),

GoodsVariations model (product variations, table 2).

'goods' => array(self::BELONGS_TO, 'Goods', 'goods_id'),

In View-product we get a model of any product

$product = Goods::model()->findByPk($product_id); // Произвольный ID, например 1234, не суть

Product variations are obtained in the most common way:

foreach($product->variations as $variation) {
             echo $variation->size . '<br />'; // Пускай в таком виде          	       
     }

The main question is how to get only unique product size values ​​using relation. Of course, you can do array_unique and so on, but even so, it can be done somehow through Activerecord.

Answer 1

Since the variations link is used not only in the context of size, you need to create a separate link for this, where in the parameters you specify a selection of only unique size values, or iterate through the array

Answer 2

Then it's easier with an array, I still don't know Yii enough to create Relations not through the built-in GII.
In Google, all the info that I found is to do it somehow through such a construction:

public function relations() {
  return array(
    'variations' => array(self::HAS_MANY, 'GoodsVariations', 'goods_id', 'distinct'=>true),
  );
}

But it throws an error.
Although this can be done by applying to the model scopes 'size'=>array('group'=>size); but I also don't know how to apply scope to the construct: $product->variations Directly to the variations relation