From: Sharon Rosner <ciconia@...>
Date: 2007-07-22T22:12:39+09:00
Subject: Re: first ruby script mysql data input

> ids = []
> res = db.query( "select id from mytable")
> while row = res.fetch_row do
>   ids << row[0]
> end
> res.free
> ids.map! { |i| i.to_i } # do this just in case mysql doesn't return integers
> # at this point you have an array of integers, how you get here is up to you
> # now, for the ruby chocolate ...
> free_ids = (1..ids.max).to_a - ids

here's the sequel version:

require 'sequel/mysql'
DB = Sequel.open('mysql://user@localhost:/mydb')
free_ids = (1..ids.max).to_a - DB[:mytable].map(:id)

best
sharon