SQL · Structured Query Language
/ ESS-cue-ell or SEE-kwl /
SQL is the language you use to ask a relational database questions — and to add, change, or remove data. Instead of writing loops to dig through files, you write one short sentence describing what you want, and the database figures out how to get it.
It reads almost like English: SELECT name FROM users WHERE age > 18 means 'give me the names of users older than 18'. The four verbs you'll lean on most are SELECT (read), INSERT (add), UPDATE (change), and DELETE (remove).
It's spoken two ways — spell it out, 'ESS-cue-ell', or say 'SEE-kwl' (people will know what you mean either way). Almost every relational database speaks SQL, so the skill carries from PostgreSQL to MySQL to SQLite with only small dialect differences.
SELECT name, email FROM users WHERE created_at > '2026-01-01' ORDER BY name;
Read just the users who signed up this year, sorted by name.
SQL is for relational databases; 'NoSQL' is the umbrella name for stores that work differently and don't use it.