Антон Иванов

/* 
$data = [
0 => ['id' => ..., 'customer_id' => ...],
1 => ['id' => ..., 'customer_id' => ...]
...
]
*/
$sql = $db->queryBuilder->batchInsert(self::$table, arrow_keys($data[0]), $data);

(new Query())->select([
    'SUM(IF(status = "1",1,0))' => 'active',
    'SUM(IF(status = "0",1,0))' => 'inactive'
]);

public function getUser()
{
    return $this->hasOne(User::class, ['id' => 'user_id']);
}

Countries::find()->where(['alive'=>1])->select(['country', 'code'])->asArray()->all();