SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 1)
   ExpressionList (children 1)
    Function mapApply (children 1)
     ExpressionList (children 2)
      Function lambda (children 1)
       ExpressionList (children 2)
        Function tuple (children 1)
         ExpressionList (children 2)
          Identifier x
          Identifier y
        Literal Tuple_(\'x\', \'y\')
      Function materialize (children 1)
       ExpressionList (children 1)
        Function map (children 1)
         ExpressionList (children 4)
          Literal UInt64_1
          Literal UInt64_0
          Literal UInt64_2
          Literal UInt64_0