SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 1)
   ExpressionList (children 1)
    Function mapFromArrays (children 1)
     ExpressionList (children 2)
      Literal Array_[\'aa\', \'bb\']
      Function map (children 1)
       ExpressionList (children 4)
        Literal \'a\'
        Literal UInt64_4
        Literal \'b\'
        Literal UInt64_5