How to count quantity with ActiveRecord?

Question

MySQL

Good afternoon.
How to count the number of cities in a table?
`id`,`user`,`country_id`,`city_id`
How to get just the number of records - understandable
<?= User::find()->count()?>
And how to calculate the number of cities a user has?
I don’t understand the query itself by counting unique cities

Answer 1

1. SELECT COUNT(DISTINCT `city_id`) AS `city_count`  FROM `user_table`;
2. SELECT `user`, COUNT(DISTINCT `city_id`) AS `city_count` FROM `user_table` GROUP BY `user`;

Answer 2

You can use a realation like stat.
Here is an example code for your case:

class User extends CActiveRecord
{
    public function relations()
    {
        return array(
            'cityCount'=>array(self::STAT, 'City', 'city_id'),
        );
    }
}