Interactive SQL Learning

Learn SQL

A structured path from zero to confident querying. Practice SELECT, JOINs, GROUP BY, and CRUD with a real SQLite engine running locally in your browser.

~3 hours of content14 lessonsRunnable SQLite examplesNo sign-up required

2Querying Data

2.1beginner

SELECT & FROM — Reading Data

Learn SELECT and FROM to read data from tables, choose columns, use aliases, and remove duplicates with DISTINCT.

12 min readStart lesson →
2.2beginner

WHERE — Filtering Rows

Filter rows with WHERE, comparison operators, AND/OR, IN, BETWEEN, LIKE, and correct NULL checks.

14 min readStart lesson →
2.3beginner

ORDER BY & LIMIT — Sorting & Pagination

Sort results with ORDER BY and paginate with LIMIT and OFFSET for top-N and page-based queries.

10 min readStart lesson →
2.4beginner

SQL COUNT() Function

Count rows with COUNT(*), COUNT(column), and COUNT(DISTINCT). Filter counts with WHERE and preview counting joined tables.

12 min readStart lesson →
2.5beginner

INNER JOIN — Combining Tables

Combine users and orders with INNER JOIN, understand PK/FK links, aliases, and avoid Cartesian products.

15 min readStart lesson →
2.6beginner

SQL CASE Expression

Add conditional logic with searched and simple CASE in SELECT and ORDER BY. Label order statuses and preview conditional aggregates.

13 min readStart lesson →
2.7beginner

GROUP BY & Aggregates

Summarize data with COUNT, SUM, AVG, MIN, MAX, GROUP BY, and HAVING filters on grouped results.

14 min readStart lesson →

3Joins & Data Modification

3.1beginner

LEFT JOIN — Include Unmatched Rows

Keep every user row even when they have no orders. Compare LEFT vs INNER JOIN and find users with zero orders using NULL checks.

14 min readStart lesson →
3.2beginner

Subqueries — Queries Inside Queries

Nest SELECT inside WHERE, FROM, and SELECT clauses. Filter with IN, compare to aggregates, and read scalar subquery results.

15 min readStart lesson →
3.3beginner

INSERT INTO — Adding Rows

Add rows to users and orders with INSERT. Respect primary keys, foreign keys, NOT NULL, and DEFAULT constraints.

12 min readStart lesson →
3.4beginner

UPDATE — Changing Data Safely

Modify existing rows with UPDATE … SET … WHERE. Avoid accidental full-table updates and update joined tables correctly.

13 min readStart lesson →
3.5beginner

DELETE — Removing Rows

Remove rows with DELETE … WHERE. Delete in FK-safe order, compare DELETE vs TRUNCATE, and never drop data without a WHERE clause.

12 min readStart lesson →

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