SQL Server SELECT LAST N Rows

Question

This is a known question but the best solution I\'ve found is something like:

SELECT TOP N *
FROM MyTable
ORDER BY Id DESC

I\'ve a table wi

Answer 1

Is "Id" indexed? If not, that's an important thing to do (I suspect it is already indexed).

Also, do you need to return ALL columns? You may be able to get a substantial improvement in speed if you only actually need a smaller subset of columns which can be FULLY catered for by the index on the ID column - e.g. if you have a NONCLUSTERED index on the Id column, with no other fields included in the index, then it would have to do a lookup on the clustered index to actually get the rest of the columns to return and that could be making up a lot of the cost of the query. If it's a CLUSTERED index, or a NONCLUSTERED index that includes all the other fields you want to return in the query, then you should be fine.