SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 1)
   ExpressionList (children 1)
    Function mapUpdate (children 1)
     ExpressionList (children 2)
      Function materialize (children 1)
       ExpressionList (children 1)
        Function map (children 1)
         ExpressionList (children 4)
          Literal \'k1\'
          Literal UInt64_1
          Literal \'k2\'
          Literal UInt64_2
      Function materialize (children 1)
       ExpressionList (children 1)
        Function map (children 1)
         ExpressionList (children 4)
          Literal \'k1\'
          Literal UInt64_11
          Literal \'k2\'
          Literal UInt64_22