SQL

The lingua franca of data. Query anything, anywhere.

⚠ pattern-based checks (code is analyzed, not compiled)

About SQL

SQL (Structured Query Language) is the standard language for relational databases. You'll use it with PostgreSQL (the engine behind Lovable Cloud / Supabase), SQL Server, MySQL, SQLite, and many more. NOTE: Your queries are validated by pattern matching, not executed against a real database. Focus on writing idiomatic, readable SQL. Keywords are case-insensitive in SQL — we accept both UPPER and lower case.

Quick-reference cheat sheet

-- SQL cheat-sheet

-- Read
SELECT col1, col2 FROM table WHERE col1 = 'x' ORDER BY col2 DESC LIMIT 10;

-- Aggregate
SELECT dept, COUNT(*), AVG(salary)
FROM employees
GROUP BY dept
HAVING COUNT(*) > 5;

-- Join
SELECT u.name, o.total
FROM users u
INNER JOIN orders o ON o.user_id = u.id;

-- Write
INSERT INTO users (name, email) VALUES ('Ada', 'ada@x.com');
UPDATE users SET email = 'a@x.com' WHERE id = 1;
DELETE FROM users WHERE id = 1;

-- DDL
CREATE TABLE notes (
  id SERIAL PRIMARY KEY,
  body TEXT NOT NULL,
  created_at TIMESTAMPTZ DEFAULT now()
);

-- CTE + window
WITH ranked AS (
  SELECT *, ROW_NUMBER() OVER (PARTITION BY dept ORDER BY salary DESC) AS rn
  FROM employees
)
SELECT * FROM ranked WHERE rn = 1;

About SQL

Tasks