SQL is 50 years old! It was first introduced in a 1974 paper titled “SEQUEL: A STRUCTURED ENGLISH QUERY LANGUAGE” by Donald Chamberlin and Raymond Boyce who were part of the IBM Research Laboratory in San Jose California.
This paper probably explains the biggest issue regarding SQL that persists to this day: its pronunciation.
I always flip between saying “sequel” and “ess cue ell” depending on context. The authors used SEQUEL as an acronym of Structured English QUEry Language. Over time this was referred to as Structured Query Language and the initialism of SQL took hold. Still, the pronunciation of sequel seems to have also stuck. Anyway, pronounce it how you want — I won’t judge.
I’ve sometimes seen people claim that SQL stands for Standard Query Language. As the above clearly shows, that is not true. And if you’ve used SQL at all with more than one database, you also have empirical evidence that there is not much standard about it beyond the main keywords.
The paper itself is only about 15 pages, so not long at all. I found this surprising as I expected it to be some lengthy and detailed specification written for academics.
But it’s not.
It starts by talking about the relational model of data, a somewhat new concept at the time (first described in 1969), and the predicate calculus, introducing a sublanguage called SQUARE, which strikes me a somewhat functional way of querying relational data. Math nerds do love their functional languages.
The authors then go on to introduce SEQUEL as a substitute for SQUARE and it’s here where we see the first syntax that you might recognize:
SELECT NAME
FROM EMP
WHERE DEPT = ’TOY’Boolean expressions in the WHERE clause are also covered along with functions in the SELECT clause. These are all things still being used to this day.
The main justification the authors use for SEQUEL is that the concepts of predicate calculus and SQUARE require “too much sophistication for the ordinary user”. I won’t argue with that!
They drive that point home by showing how to get data results using some example queries, first by using SQUARE and then comparing to the SEQUEL equivalents. Their first query is this:
Find the names of managers who manage more than ten employees.
Note that for this example, there is a previously defined database with one of the tables as follows:
EMP (NAME, DEPT, MGR, SAL, COMM)
The SQUARE example looks like this:
I’m not going to even try to explain this. Read the paper if you’re curious.
Here’s the SEQUEL version:
SELECT MGR
FROM EMP
GROUP BY MGR
WHERE COUNT (NAME) > 10Well, now. That certainly makes more sense to me. I’ll bet that everyone reading this knows exactly how to parse out the SEQUEL command. It would actually work as-is in a database such as SQLite today!
There are other examples in the paper as well. Like I said, it’s somewhat short so you might find it to be an interesting read.
Happy 50th Birthday, SEQUEL (SQL)!!
Paul learned to program in BASIC at age 13 and has programmed in more languages than he remembers, with Xojo being an obvious favorite. When not working on Xojo, you can find him talking about retrocomputing at Goto 10 and on Mastodon @lefebvre@hachyderm.io.