When counting deleted records from the database, I realized that sqlite_changes() will return 0 if you are deleting all the records without including a WHERE clause.
So after "DELETE FROM users" sqlite_open() will print 0 even if rows where deleted, but if you use "DELETE FROM users WHERE 1" you will get the right result.
I had this problem on versions 5.0.4 and 4.4.0 under Windows servers.