class Sequel::JDBC::AS400::Dataset

def select_sql
  return super unless o = @opts[:offset]
  l = @opts[:limit]
  order = @opts[:order]
  dsa1 = dataset_alias(1)
  dsa2 = dataset_alias(2)
  rn = row_number_column
  irn = Sequel::SQL::Identifier.new(rn).qualify(dsa2)
  subselect_sql(unlimited.
      from_self(:alias=>dsa1).
      select_more(Sequel::SQL::QualifiedIdentifier.new(dsa1, WILDCARD),
      Sequel::SQL::WindowFunction.new(SQL::Function.new(:ROW_NUMBER), Sequel::SQL::Window.new(:order=>order)).as(rn)).
      from_self(:alias=>dsa2).
      select(Sequel::SQL::QualifiedIdentifier.new(dsa2, WILDCARD)).
      where(l ? ((irn > o) & (irn <= l + o)) : (irn > o))) # Leave off limit in case of limit(nil, offset)
end