Sadly, it doesn't handle dropping columns well in sqlite. Actually, it was news to me that DROP COLUMN has been added into sqlite somewhat recently, but certainly the version you'll get on most devices doesn't include it.

But anyway, from the example for sqlite, I added "x integer not null," to the original table, and was greeted with "-- Skipped: ALTER TABLE books DROP COLUMN x". Then ticked the "Enable DROP" and got the same, except with the line uncommented.

Such a shame, this is one thing that would make a lot of difference. FWIW, the standard way of doing this is creating a temporary table with the new data, dropping the original table, and recreating the new table, copying the data across and deleting the temporary. It's kind of a shame that it doesn't automate that, and this is one of those things that's incredibly easy to mess up if you're not careful, especially if there are constraints involved.

If it just does the easy stuff, you might as well just do it by hand.