SQL is the standard language for querying and managing relational databases. It was developed at IBM in the 1970s and standardized by ANSI in 1986. The language has aged well. The core commands have changed little. SELECT, INSERT, UPDATE, DELETE, CREATE, ALTER, DROP. These verbs do most of the work. Every major relational database supports them. The dialects differ in details, but the fundamentals are consistent. Learn SQL once and you can work with MySQL, PostgreSQL, SQL Server, Oracle, and SQLite.

SQL is declarative. You describe what you want, not how to get it. The database's query planner decides the execution strategy. That abstraction makes SQL accessible. It also means that two queries asking the same question can perform very differently. The planner chooses based on statistics, indexes, and cost estimates. Writing efficient SQL requires understanding how the planner thinks. SQL has grown beyond basic queries. Window functions, common table expressions, and JSON operators added capabilities that once required procedural code. Some databases support stored procedures and triggers that run logic inside the database. SQL is not just for querying anymore. It is a full data manipulation language. It is also the lingua franca of data work. Analysts, engineers, and scientists all speak it. If you work with data, you learn SQL.

SQL command categories

• DQL — SELECT, query data
• DML — INSERT, UPDATE, DELETE, modify data
• DDL — CREATE, ALTER, DROP, define structure
• DCL — GRANT, REVOKE, control access
• TCL — COMMIT, ROLLBACK, manage transactions

SQL is the language of data. It has outlasted every competitor and every prediction of its decline. Learn it.