You might’ve heard some developers pronouncing it as “S-Q-L” [ ˈɛs kjuː ˈɛl ] and others using “sequel” [ ˈsiːkwəl ]. I hear them both and it can start an argument anytime. So what’s the right way to pronounce it?

On StackExchange, there seems to be a norm that those who work on Microsoft dev platform tend to pronounce it “sequel” more, while those from Linux-y background such as Postgres or MySQL are more likely to pronounce it the other way.

According to wikipedia:

SQL was initially developed at IBM by Donald D. Chamberlin and Raymond F. Boyce after learning about the relational model from Ted Codd in the early 1970s. This version, initially called SEQUEL (Structured English Query Language), was designed to manipulate and retrieve data stored in IBM’s original quasi-relational database management system, System R, which a group at IBM San Jose Research Laboratory had developed during the 1970s. Chamberlin and Boyce’s first attempt of a relational database language was Square, but it was difficult to use due to subscript notation. After moving to the San Jose Research Laboratory in 1973, they began work on SEQUEL.[15] The acronym SEQUEL was later changed to SQL because “SEQUEL” was a trademark of the UK-based Hawker Siddeley aircraft company.

In short, SQL was originally called sequel. Due to a legal challenge, the name was changed to SQL. So was the pronunciation, I guess.

See from MySQL official docs:

The official way to pronounce “MySQL” is “My Ess Que Ell” (not “my sequel”), but we do not mind if you pronounce it as “my sequel” or in some other localized way.

And even on Oxford Dictionaries, it’s pronounced as S-Q-L.

Not quite clear yet, but ‘S-Q-L’ [ ˈɛs kjuː ˈɛl ] seems to be more official.

Sometimes I heard ‘squirrel’.