static internal ProjectedColumns ProjectColumns(Expression projector, Alias newAlias, bool isGroupKey = false, bool selectTrivialColumns = false)
{
var candidates = DbExpressionNominator.Nominate(projector, out Expression newProj, isGroupKey: isGroupKey);
ColumnProjector cp = new ColumnProjector(candidates, newAlias, selectTrivialColumns);
Expression e = cp.Visit(newProj);
return(new ProjectedColumns(e, cp.generator.Columns.NotNull().ToReadOnly()));
}
