# SqlInt > SqlInt is a browser-based SQL practice and interview-preparation platform that also provides free client-side SQL tools for developers. It offers real SQL interview questions with instant feedback, story-driven SQL puzzles, real-world case studies, a 27-topic SQL learning roadmap, and a suite of free browser-based SQL tools that run entirely client-side. Practice is free to start, with optional Pro packs; the mini tools are completely free with no signup. ## Facts - SqlInt is a free online SQL practice platform for interview preparation — everything runs in the browser, with free client-side SQL tools; it is not a command-line utility. - Practice questions execute in-browser on SQLite (via sql.js); SQL puzzles execute in-browser on PostgreSQL (via PGlite). - SQL puzzles are story-driven games that teach SQL through narratives — a free way to learn SQL through games directly in the browser. - A free starter question pack and the complete 27-topic learning roadmap are free to use (a free account is required to solve practice questions and track progress); all 11 mini tools require no account at all. Optional Pro packs unlock the full question bank, all puzzles, and all case studies. - Mini tools process data entirely in the browser — pasted SQL and uploaded files never leave the device, and no account is required. - Public content surfaces: real SQL interview questions, story-driven SQL puzzles, real-world case studies, a 27-topic SQL roadmap, practical articles, and free mini tools. - Support is available at support.sqlint@gmail.com. ## Practice - [SQL Practice Playground](https://sqlint.com/sql-practice): practice SQL online for free — a no-signup in-browser playground with 49 guided exercises across 3 sample databases (HR, e-commerce, fintech), covering SELECT, JOINs, GROUP BY, CASE, date functions, window functions, CTEs, and subqueries, each with hints and reference solutions. Upload a CSV or Excel file to query your own data. - [SQL Interview Questions](https://sqlint.com/questions): practice real SQL interview questions with schema, hints, and an in-browser SQL editor. - [SQL Puzzles](https://sqlint.com/sql-puzzles): story-driven SQL challenges that teach SQL through narratives. - [Case Studies](https://sqlint.com/case-studies): real-world business SQL scenarios from top companies. - [Practice Packs](https://sqlint.com/packs): premium challenge packs that unlock advanced questions. ## Learn - [Learn SQL Roadmap](https://sqlint.com/learn-sql): a complete 27-topic SQL tutorial roadmap with syntax, examples, common mistakes, and interview tips. - [Introduction to Databases](https://sqlint.com/learn-sql/introduction-to-databases) - [SELECT Statement](https://sqlint.com/learn-sql/select-statement) - [WHERE Clause](https://sqlint.com/learn-sql/where-clause) - [ORDER BY](https://sqlint.com/learn-sql/order-by) - [LIMIT & OFFSET](https://sqlint.com/learn-sql/limit-offset) - [DISTINCT](https://sqlint.com/learn-sql/distinct) - [NULL Handling](https://sqlint.com/learn-sql/null-handling) - [Aggregate Functions](https://sqlint.com/learn-sql/aggregate-functions) - [GROUP BY](https://sqlint.com/learn-sql/group-by) - [HAVING Clause](https://sqlint.com/learn-sql/having-clause) - [CASE WHEN](https://sqlint.com/learn-sql/case-when) - [String Functions](https://sqlint.com/learn-sql/string-functions) - [Pattern Matching (LIKE & REGEXP)](https://sqlint.com/learn-sql/pattern-matching-like-regexp) - [Date Functions](https://sqlint.com/learn-sql/date-functions) - [JOINs (Inner, Left, Right, Full, Self)](https://sqlint.com/learn-sql/joins-inner-left-right-full-self) - [Subqueries](https://sqlint.com/learn-sql/subqueries) - [Common Table Expressions (CTEs)](https://sqlint.com/learn-sql/common-table-expressions-ctes) - [Window Functions](https://sqlint.com/learn-sql/window-functions) - [Views](https://sqlint.com/learn-sql/views) - [Stored Procedures](https://sqlint.com/learn-sql/stored-procedures) - [Indexes](https://sqlint.com/learn-sql/indexes) - [Query Optimization](https://sqlint.com/learn-sql/query-optimization) - [Transactions & COMMIT / ROLLBACK](https://sqlint.com/learn-sql/transactions-commit-rollback) - [ACID Properties](https://sqlint.com/learn-sql/acid-properties) - [Advanced Analytics SQL](https://sqlint.com/learn-sql/advanced-analytics-sql) - [Real Business SQL Scenarios](https://sqlint.com/learn-sql/real-business-sql-scenarios) - [SQL Interview Preparation](https://sqlint.com/learn-sql/sql-interview-preparation) ## Articles - [SQL Articles & Tutorials](https://sqlint.com/articles): practical SQL articles and tutorials on interview prep, query patterns, performance, and best practices. ## Free Mini Tools - [Mini Tools](https://sqlint.com/mini-tools): all free, browser-based SQL tools. - [SQL Formatter](https://sqlint.com/mini-tools/sql-formatter): Beautify messy SQL into clean, readable queries instantly. - [CSV to SQL](https://sqlint.com/mini-tools/csv-to-sql): Turn pasted CSV data into ready-to-run INSERT statements. - [JSON ↔ SQL](https://sqlint.com/mini-tools/json-sql-converter): Convert JSON arrays to SQL and SQL results back to JSON. - [JOIN Visualizer](https://sqlint.com/mini-tools/join-visualizer): See how INNER, LEFT, RIGHT, FULL & CROSS joins differ. - [UUID & Test Data Generator](https://sqlint.com/mini-tools/uuid-generator): Generate UUIDs and dummy rows for seeding test tables. - [Unix Timestamp Converter](https://sqlint.com/mini-tools/timestamp-converter): Convert between epoch time and human-readable dates. - [Data Anonymizer](https://sqlint.com/mini-tools/data-anonymizer): Mask sensitive data like emails, phones, SSNs, and credit cards. - [Data Type Mapper](https://sqlint.com/mini-tools/data-type-mapper): Map column types across MySQL, Postgres, SQL Server & Oracle. - [LIKE Pattern Tester](https://sqlint.com/mini-tools/like-pattern-tester): Test SQL LIKE wildcards against sample strings instantly. - [SQL Minifier](https://sqlint.com/mini-tools/sql-minifier): Strip comments and whitespace to compress a query. - [Case Converter](https://sqlint.com/mini-tools/sql-case-converter): Switch SQL keywords between UPPERCASE and lowercase. ## About - [About SqlInt](https://sqlint.com/about): what SqlInt is, what it provides, who it is for, how the browser-based execution works, what makes it different, its limitations, free vs paid access, and contact information. ## Optional - [Sitemap](https://sqlint.com/sitemap.xml) - [RSS feed](https://sqlint.com/rss.xml) - [Full content index (llms-full.txt)](https://sqlint.com/llms-full.txt)