SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 1)
   ExpressionList (children 1)
    Function substring (children 1)
     ExpressionList (children 3)
      Function materialize (children 1)
       ExpressionList (children 1)
        Function CAST (children 1)
         ExpressionList (children 2)
          Literal \'abcdefgh\'
          Literal \'FixedString(8)\'
      Function materialize (children 1)
       ExpressionList (children 1)
        Literal Int64_-2
      Function materialize (children 1)
       ExpressionList (children 1)
        Literal Int64_-2
