Kazakami commented, on September 20, 2012 at 6:55 p.m.:

Three tables:person (id int, name varahcr)job (id int, title varahcr)person2job (person int, job int)Then add one row per allowed person/job combination in person2job.All people who can do, say, washing up is then expressed byselect p.name from job j inner join person2job p2j on j.id = p2j.job inner join person p on p2j.person = p.id where j.name = washing up'or if you already know the job id rather than its name, that simplifies toselect p.name from person2job p2j inner join person p on p2j.person = p.id where p2j.id = $known_id