Keep only N last records in SQLite database, sorted by date

Question

I have an SQLite database that I need to do the following: Keep only last N records, sorted by date. How do you do that?

Answer 1

Assuming you have an id column which is a sequential number (AUTO INCREMENT), you can use the following:

DELETE FROM table_name
WHERE id < (
    SELECT MIN(id)
    FROM (SELECT id
          FROM table_name
          ORDER BY id DESC
          LIMIT num_of_records_to_keep))

The same query can be used when using a timestamp column (simply replace id with your timestamp column)