>I have a log table with 4000 rows, each with a datetime stamp of when an action occured. I am trying to do a "date diff" between each row, and only show those rows that have taken longer than n seconds. I'm trying to get away from doing a table scan, does anyone have any help for doing it with pure SQL?

select * ;
from logtable lt ;
where lt.timestamp-lnGap > ;
(select max(timestamp) from logtable where timestamp < lt.timestamp)