How can i use ColumnExpr without it clears select command

[n0bode]

Hi folks, I have a problem, i need to count amount row in table and also get each row. So, i need a field to how amount rows and the rows as results.

My First question is: Can i use tag struct as expression function to override column at runtime? like that:

type Model struct{
   tableName struct{} `pg:"hobbits"`
   Name string `pg:"name"`
   Rows int `pg:"count(0) over ()"
}

Second question: exists a way ColumnExpr doesn't clear the select that is using columns of model?

db.Model(Model).ColumnExpr("count(0) over () as Rows").Select()

generates this:

SELECT count(0) over () as "Rows" FROM hobbits

INSTEAD OF

SELECT name, count(0) over () as "Rows" FROM hobbits

I know, i can use two queries to do that. But, i think this way it is more performant than two queries, in time question.