Welcome to XCODX Online Compiler
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SQLite is the most deployed database engine in the world — a single self-contained C library that runs inside every Android and iOS device, every major web browser, aircraft systems, and countless apps, with no server process anywhere in sight. That same zero-configuration design makes it the fastest way to learn and practice SQL: there are no credentials, no connection strings, and no daemon to start — you just write statements and read results. This page is the SQLite command-line shell in the cloud: your whole script is treated as one .sql file and executed top to bottom, so you CREATE tables, INSERT rows, and then query them with joins, GROUP BY, CTEs, and window functions, with each SELECT's rows printed to the terminal. Because it is the real engine, constraints, type affinity, and error messages match sqlite.org exactly. The SQLite version is shown in the badge above the editor.
-- One self-contained .sql script: schema, data, and queries
.mode column
.headers on
CREATE TABLE employees (
id INTEGER PRIMARY KEY,
name TEXT NOT NULL,
dept TEXT NOT NULL,
salary INTEGER NOT NULL
);
INSERT INTO employees (name, dept, salary) VALUES
('Ava', 'Engineering', 145000),
('Liam', 'Engineering', 120000),
('Mia', 'Sales', 98000),
('Noah', 'Sales', 88000),
('Zoe', 'Design', 110000);
-- Headcount and average pay per department
SELECT dept,
COUNT(*) AS headcount,
ROUND(AVG(salary)) AS avg_salary
FROM employees
GROUP BY dept
ORDER BY avg_salary DESC;
-- Rank each person within their department (window function)
SELECT name, dept, salary,
RANK() OVER (PARTITION BY dept ORDER BY salary DESC) AS dept_rank
FROM employees
ORDER BY dept, dept_rank;SQLite is the ideal place to drill the SQL that appears in almost every analyst, backend, and data-engineering interview — joins, GROUP BY with HAVING, correlated subqueries, and the window functions (ROW_NUMBER, RANK, LAG) that separate strong candidates — because you can stand up a tiny dataset and query it in seconds. It is equally useful for database-course homework, for sketching a table design before committing to a real migration, or for pasting an unfamiliar query from a code review to see exactly what it returns. Where it is not the right tool is anything about server operation and scale: SQLite allows only one writer at a time and is built for single-file, embedded use, so questions about connection pooling, replication, or high-concurrency writes belong to PostgreSQL or MySQL. For learning the SQL language itself, though, the engine speaks the same core dialect those servers do for the vast majority of everyday queries.
It is the genuine SQLite engine — the same C library shipped on billions of devices — running your statements top to bottom against a real, temporary database. Result rows print as each SELECT executes, and constraints, type affinity, and error messages behave exactly as documented at sqlite.org, because this is that software rather than a reimplementation.
No — each run creates a brand-new, empty database that is discarded the moment the script finishes, so nothing carries over from a previous run. That is actually convenient for practice: keep your CREATE and INSERT statements at the top of the editor and every run rebuilds the same data, so results are perfectly reproducible. To save work, save the .sql script itself.
You provide data by writing it into the script: CREATE TABLE followed by INSERT statements is the intended workflow, and the whole editor is executed as a single .sql file. There is no persistent filesystem to upload a CSV to and no network to reach a remote file, so .import from disk and ATTACH to an external database are not options here — bake a small sample dataset into the script instead.
Yes. Modern SQLite includes WITH clauses and recursive CTEs, the full window-function suite (ROW_NUMBER, RANK, DENSE_RANK, LAG, LEAD, and running aggregates with OVER), UPSERT via ON CONFLICT, and the JSON functions such as json_extract. That makes this a legitimate ground for interview-level SQL, not just basic SELECTs.
No — the sandbox has no network access, so there is no way to reach an external server, and this runtime is SQLite specifically rather than a MySQL or Postgres client. Use it to practice the SQL language and prototype queries against sample data, then run the finished query against your real database in its own client.
The core — SELECT, JOIN, GROUP BY, subqueries, CTEs, and window functions — is standard and transfers directly. SQLite differs at the edges: it uses flexible type affinity instead of strict column types, has its own set of date and time functions, and omits some server features, so a handful of statements may need tweaks when you move to MySQL or Postgres. For learning and interview practice, the overlap covers the vast majority of everyday queries.
main.sqlsqlnot applicableCREATE TABLE hello (message TEXT);
INSERT INTO hello VALUES ('Hello from SQLite3!');
INSERT INTO hello VALUES ('Welcome to XCODX Online Compiler!');
SELECT * FROM hello;