Changing the select parameters by calling ->select twice? - database

Question

I had a query:
$query =
Yii::app()->db->createCommand()->setFetchMode(PDO::FETCH_OBJ)
->select('*')
->from('products p')
->limit(5);
And then I got results:
$result = $query->queryAll();
How can I use the existing query object, without rewriting it, to re-instantiate the values for "select" and "limit". I want to change select to "count(p.productid)" and unset limit. I tried the following but it does not work:
$query =
Yii::app()->db->createCommand()->setFetchMode(PDO::FETCH_OBJ)
->select('*')
->from('products p')
->limit(5);
$result = $query->queryAll();
$query =
$query
->select('count(p.productid)')
->limit(-1);
$result2 = $query->queryRow();
This still returns the result of the first select?
EDIT
Basically, I want to RESET the select. It looks like it builds on the select. So, I think you can do this:
$query =
$query->select('something')
->select('somethingElse')
->select('somethingMoreStuff');
My problem is that I want to "reset" the select. So basically UNDO these selects. Is this possible?

Answer 1

Why don't you do:
$intialQuery =
Yii::app()->db->createCommand()->setFetchMode(PDO::FETCH_OBJ)
->from('products p');
$query = $intialQuery
->select('*')
->limit(5);
$query2 = $intialQuery
->select('count(p.productid) as number')
->limit(-1);
$result = $query->queryAll();
$result2 = $query2->queryRow();