Sometimes you might fall out with friends on Facebook so that you don't even want them to see your restricted page. You'd want to delete your relationship (it's actually likely that Facebook retains the connection but flags it as 'deleted', that isn't important here). The police might also find that a crook is in fact innocent and then want to delete their criminal record. We need a DELETE command to do all of these things, to permanently delete records from databases. Imagine that we find out that Geoff was framed and he is completely innocent:
DELETE FROM crooks WHERE name = 'Geoff'
DELETE FROM crooks WHERE numScars >= 4 AND gender = 'female'
DELETE FROM crooks WHERE DoB >= 1999