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
        Literal UInt64_0
        Function toNullable (children 1)
         ExpressionList (children 1)
          Literal UInt64_0
