What is the difference between sequel and SQL?

The definition of the Word Sequel is "that which follows in consequence of what has previously happened" Ie. The Godfather 2 was the sequel to The Godfather.

SQL on the other hand, was originally an acronym for Structured Query Language. SQL is a standard interactive and programming language for getting information from and updating a database.

SQL (correctly pronounced "ess cue ell,") is in slang referred to as "Sequel" as a method of pronouncing the 3 letter acronym. The 'sequel' pronunciation is a carryover from when there was actually a SEQUEL language.