How to select from three unrelated yii tables?

Question

Yii

Hello, you need to make a selection from 3 tables together, they are not related, and they differ in structure by half. How to implement this using criteria or cdcommand?
I tried something like this, but the selection did not work ...

$users = Yii::app()->db->createCommand()
        ->select('*')
        ->from('char_quick_donate, char_user_donate, char_anonym_donate')
        ->queryAll();

Thank you!

Answer 1

What does "unrelated, and half different in structure" mean? If they are not connected, then it means to select them with three queries. I think you should read a few manual articles about SQL.