In relationship query, a tablename.id field was added into the query string automatically, how I can forbid it?

[smartbox-jiandonghan]

In the relationship, user table is the parent table, post table is the child table.
in post table, the primarykey is not 'id' or 'post_id'. it's 'post_number' + another field, a composite primary key.
I have declared the relationship in model user and model post with 'hasMany' and 'belongsTo'.

in the user query resolve method, I have the following code.
''''''

    $fields = $getSelectFields();
    $select = $fields->getSelect();
    $with = $fields->getRelations();

    $users = User::select($select)->with($with)
    ->where('user_id', $args['user_id']);
    
    return $users->get();  

''''''
then in the query result. I got an error: "post.id: invalid identifier . select ..... post.id from ......."

My issue is: why the post.id was added to the query string. It may because of some eloquent's by default operations? how I can forbid it?

Can we have other alternative solutions to use the relationship query?

Great thanks for your help.