SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 1)
   ExpressionList (children 1)
    Function cityHash64 (children 1)
     ExpressionList (children 1)
      Function map (children 1)
       ExpressionList (children 4)
        Literal UInt64_1
        Literal \'a\'
        Literal UInt64_2
        Literal \'b\'