A post titled "Learn SQL Once, Use It for 30 Years" hit the front page of r/programming this week (307 points, 48 comments). The claim sounds like the kind of thing a database vendor would put on a billboard, so I went looking for the part that holds up. It turns out the longevity is not marketing. It is a property of how the language was designed, and it is the reason SQL is one of the few skills on a developer's resume that does not quietly expire.
I run a site that compares developer tools, which means I spend a lot of time watching technologies rise, peak, and get replaced. Most of what you learn in this field has a half-life measured in single-digit years. The framework you mastered in 2019 is legacy by 2024. SQL is the strange exception, and the reasons are worth understanding before you decide where to spend your next month of learning.
Where the staying power comes from
SQL did not start as a language. It started as a math paper. In 1970, Edgar Codd published "A Relational Model of Data for Large Shared Data Banks," which proposed organizing data into tables of rows and columns with formal rules for combining them. IBM built a query language on top of that model in the mid-1970s, called it SEQUEL, and later renamed it SQL after a trademark conflict. The important detail is the order: the model came first, the language second. SQL is a surface over a mathematical foundation that has not needed to change.
