Count query with group in class extends \yii\db\Query

[sallfris]

What steps will reproduce the problem?

1. Create class QueryMyDb extends \yii\db\Query
2. Modify function in QueryModified

    public function createCommand($db = null)
    {
        if ($db === null) {
            $db = Yii::$app->get('myDb');
        }
        return parent::createCommand($db);
    }

3. Execute request

(new QueryMyDb())->from('table')
            ->groupBy('column')
            ->count();

What is the expected result?

Query to myDb

What do you get instead?

Query to db

Additional info

Problem this If use (new static()), the query will be correct

Q	A
Yii version	2.0.47
PHP version	7.2
Operating system	unix

[lubosdz]

What's your ../config/main.php section for databases ?

[kamarton]

What's your ../config/main.php section for databases ?

The configuration is not relevant. The problem is that Query#queryScalar() create a instance with new self(), ignoring the request initiated from the modified class.

[lubosdz]

I solved this some time ago by class SwitchableConnection extends \yii\db\Connection, but it was quite complicated. I like suggested solution in PR - points out nicely the difference static vs self, though I am curious about tests. Current failure does not seem related to this PR, but to Generators support in JSON helper #19766.

[rhertogh]

@lubosdz Current failure does not seem related to this PR, but to Generators support in JSON helper

I ran in the same issue. I've created a PR to fix the unit test (https://github.com/yiisoft/yii2/pull/19798).

[samdark]

@rhertogh, @bizley is there something to do for this one besides unit test fix that was done?

[bizley]

I think we should changed the mentioned call to static (instead of self).

[samdark]

OK. @bizley do you have time for a pull request? I plan to release soon.

[rob006]

https://github.com/yiisoft/yii2/pull/17346#issuecomment-532758630

[bizley]

Ech, right. Not sure what to do then.