Yii2 : How to write distinct SQL query?

Question

I want to implement following SQL queries in Yii 2 but with no success.

This should give total number of unique company names:

Answer 1

I hope this sample is useful for you

 $names = Yii::$app->db->createCommand('SELECT  count(DISTINCT(company_name)) as name FROM clients')
    ->queryAll();

for access the the data

foreach ($names as $name){
    echo $name['name'];
}