How to optimize the "order by" & "limit" query?

[Jiangyubao Jiangyubao]

Hello, I am a student from Beijing China.I create a table named Employee in MySQL5 and insert 500000 records.Then I send the following query string to mysql client to execute:
(1)select * from Employee as e order by e.id desc limit 499990,10
(2)select * from Employee as e limit 499990,10

The first query take about 4 seconds to complete, but the second query take only about 0.35 seconds to eomplete.

Will anybody tell me how to optimize such query?



Edited 1 time(s). Last edit at 12/18/2006 09:51AM by Jiangyubao Jiangyubao.