creocoder / yii2-nested-sets

     * @param integer|null $depth the depth

     * @return \yii\db\ActiveQuery

     */

    public function parents($depth = null)

    {

        $condition = [

            'and',

            ['<', $this->leftAttribute, $this->owner->getAttribute($this->leftAttribute)],

            ['>', $this->rightAttribute, $this->owner->getAttribute($this->rightAttribute)],

        ];

        if ($depth !== null) {

            $condition[] = ['>=', $this->depthAttribute, $this->owner->getAttribute($this->depthAttribute) - $depth];

        }

        $this->applyTreeAttributeCondition($condition);

        return $this->owner->find()->andWhere($condition)->addOrderBy([$this->leftAttribute => SORT_ASC]);

    }

    /**

     * Gets the children of the node.

     * @param integer|null $depth the depth

     * @return \yii\db\ActiveQuery

     */

    public function children($depth = null)

    {

        $condition = [

            'and',

            ['>', $this->leftAttribute, $this->owner->getAttribute($this->leftAttribute)],

            ['<', $this->rightAttribute, $this->owner->getAttribute($this->rightAttribute)],

        ];

        if ($depth !== null) {

            $condition[] = ['<=', $this->depthAttribute, $this->owner->getAttribute($this->depthAttribute) + $depth];

        }

        $this->applyTreeAttributeCondition($condition);

        return $this->owner->find()->andWhere($condition)->addOrderBy([$this->leftAttribute => SORT_ASC]);

    }

    /**

     * Gets the leaves of the node.