SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 1)
   ExpressionList (children 1)
    Function substring (children 1)
     ExpressionList (children 3)
      Literal \'abcdefgh\'
      Function materialize (children 1)
       ExpressionList (children 1)
        Literal UInt64_2
      Literal Int64_-2