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)
        Literal \'abcdefgh\'
      Function materialize (children 1)
       ExpressionList (children 1)
        Literal Int64_-2
      Function materialize (children 1)
       ExpressionList (children 1)
        Literal Int64_-1