Trying to do something similar to [this question](https://stackoverflow.com/questions/37830594/yii2-how-to-add-two-fields-in-orderby-of-find), but need to sort NULLS LAST for MySQL

something like...

```
$query->MODEL_NAME::find(); 
$query->orderBy(['column_1' => 'IS NULL','column_1'=> SORT_DESC]);

```

though this syntax is wrong. Thanks!

When I try `orderBy('column_1 IS NULL ASC, column_1 desc')` i get the error

> 
> SQLSTATE[42S22]: Column not found: 1054 Unknown column. The SQL being
>  executed was: `SELECT * FROM 'table' ORDER BY 'due_date IS NULL'`
> 
> 
> 

NOTE: had to replace backticks with single quotes in the error above in order for it to display here.