Question about search speed

[jda]

I have a built-in search that finds the last 20 records entered. Each record has a unique sequential number (1..N) in the field "id", and this is the query:


     SELECT * FROM mytable WHERE id > (select max(id) - 20 from mytable)


It works, but is very slow. With a database of ~7000 records it takes ~20 seconds.

Is there a way to optimize this (using V4.9.1, Mac OS X).

Thanks,

Jon