SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 1)
   ExpressionList (children 1)
    Function sum (children 1)
     ExpressionList (children 1)
      Function if (children 1)
       ExpressionList (children 3)
        Identifier dummy
        Function materialize (children 1)
         ExpressionList (children 1)
          Literal UInt64_0
        Function materialize (children 1)
         ExpressionList (children 1)
          Function toNullable (children 1)
           ExpressionList (children 1)
            Literal UInt64_0
