SQL is a well-established standard and is implemented in a consistent way across a variety of DBMS’s. In my career, I’ve worked with MySql, SQLServer, SQLite, and Oracle. My knowledge of SQL goes over pretty unchanged.

My code for all of these systems is hopelessly incompatible.

I can’t grab SQL from my node app and put it in my iPhone app, because there’s more to it than the SQL. The SQL is embedded in the host language and often abstracted in a library (like TypeORM, Django, CoreData, or JDBC). These languages and libraries are completely incompatible with each other. I tend to use ORMs, but this would be true even without them because you often want some kind of composability with your SQL clauses. You’d have to build that in the host language and then spread partial SQL strings around your code.

Even if you tried to keep your SQL pure and outside the host language, you’d run into portability issues. Each of the individual DBMS vendors add to their implementation of SQL in mutually incompatible ways (mostly for good reason). User needs often outpace the speed of the standardization bodies, and so the vendors need to innovate outside of the standard.

You run into this with web programming because there is no standard way in SQL to grab rows N through M from a SELECT. In order to implement paging, you need to be able to do this efficiently. SQL has also been extended in incompatible ways to store external blobs. Even simple things, like dates, are not consistent.

And, I haven’t even mentioned stored procedures.

But, even though SQL doesn’t help me port my programs, SQL is a good way for me to think about data. I can show it to other developers or DBA’s, and we can have a conversation. Most of my data code will be based around SQL in some way and will be understandable to any developer who knows SQL.

My programs get many benefits from SQL, but not portability. And this is true with standards in general. Instead of Java’s promise to “write once, run anywhere”, we live in a world that React Native calls “learn once, write anywhere”, and it’s not bad.