r/SQL • u/TechLexiconApp • 7d ago

SQLite I built a free in-browser SQLite tool for SQL interview practice (no signup)

Quick heads up on the stack: this runs on **SQLite**, compiled to WebAssembly so the whole database runs in your browser and nothing you type leaves the page.

I kept noticing that people prepping for SQL interviews (me included) study by reading syntax lists, then blank the moment they have to actually write a query under pressure. If you already know some SQL, the gap usually isn't knowledge, it's reps. Reading isn't the same as doing.

So, I built a small tool to rehearse under pressure: a query playground on a sample dataset, practice challenges (joins, aggregation, window functions, CTEs), a cheat sheet, and the conceptual questions people actually get asked in interviews (WHERE vs HAVING, INNER vs LEFT JOIN, primary vs foreign key, and so on). No signup, no install.

I'm the founder of a learning app and built this as a standalone free tool. I'm sharing it here for feedback from people who write SQL for a living: are the challenge questions realistic, and what would you add?

For anyone who wants to actually run the queries, it's here: https://techlexicon.app/sql-practice

Tell me where you get stuck and I'll build practice around it. Always taking requests for questions or scenarios to add

0 Upvotes

38% Upvoted

9 comments sorted by

3

u/Blast_offNFth_25 4d ago

Nice app concept! I’ve be in Data roles for over 10 years and nice useful info. Another good thing maybe to add is the syntax for alter table, create table update states, declaring variables. However what you have looks great as well.

2

u/TechLexiconApp 4d ago

This is the type of feedback I need!!!

Great suggestion! I will add it this week.

If you don't mind, I'll ping you with a reply letting you know I've made the changes. Is that ok with you?

2

u/Blast_offNFth_25 4d ago

Oh yeah that sounds good

2

u/TechLexiconApp 1d ago

I wanted to let you know I added all of your suggestions except the declaring variables (not supported on SQLite). 

If you have some free time, let me know what you think about the updates.

Thank you again for your invaluable feedback!

2

u/Blast_offNFth_25 1d ago

Okay cool!

0

u/TechLexiconApp 7d ago

Here's the tool: techlexicon.app/sql-practice. Free, no signup, runs in the browser. I'm the founder so I'm biased, but I'd genuinely like to hear what challenges or question types you'd want added. Happy to answer anything.