Codeginter - 以相反的顺序分页

Question

我使用Codegniter分页库进行分页。一切正常。但我想以相反的顺序分页。

For Ex : If there are 100 records, 10 records per page.
Right now first page display 1 to 10 records.
But I want first page should display 91 to 100 records. And second page will display 81 to 90 and so on.. 
Without changing the mysql Query.
'SELECT * FROM tbl_user ORDER BY id ASC'

我应该在库中更改什么。