Both platforms get you SQL practice. They solve different problems. DataLemur is a curated interview question library. SQL Quest is a learning loop — wrong-answer diagnostic, AI Coach, adaptive Skillmap. Here's the honest side-by-side, including where DataLemur wins.
299 challenges · 226 free
Every Easy & Medium, 6 Hard previews
AI Coach (Claude)
Explains why you're wrong
No signup to start
Browser-only, instant
Pick SQL Quest if…
You're stuck staring at "incorrect" with no idea why. You've gone through DataLemur's free tier and want a coach, not just more questions. You're learning SQL from zero. You want a roadmap that adapts as you improve, not a flat list of problems. You want to track which of the 9 SQL skill areas you're weak in.
Pick DataLemur if…
You're 2-3 weeks out from a Meta/Google/Amazon interview and want a curated bank of "this is the actual question they ask" problems with verified provenance. You learn well from solution videos. You already know SQL solidly and just need volume on real questions.
Use both if…
You want maximum coverage. SQL Quest free gives you the diagnostic loop and adaptive path. DataLemur Premium gives you the company-specific question depth. Many users keep SQL Quest open as their tutor and DataLemur as their question library.
12 features that actually matter when you're prepping. Green = built-in, gray = not really, neutral = both have it. Last verified September 2026 — DataLemur figures from datalemur.com/pricing on 2026-09-07.
Verified September 2026 against datalemur.com/pricing (2026-09-07). DataLemur features and pricing change — check their site for the latest. We update this page when material differences appear.
Every SQL Quest user we've talked to who switched from DataLemur cited at least one of these. They're the gaps you hit at the intermediate level.
Your query runs. The output is wrong. DataLemur shows "incorrect" + the expected table. You squint at two grids trying to spot the diff. SQL Quest tells you: "Row 3, column total_revenue, your value is 4,820 — expected 4,920. You included refunded orders." One line, problem identified.
Stuck on a window function? Type "why is my RANK() giving ties when I expected unique ranks?" in the AI Coach panel. Claude reads your query, your schema, the expected output, and tells you to swap to ROW_NUMBER() with an explicit tie-breaker. DataLemur sends you to Discord.
Closed the tab on Tuesday. Came back Friday. SQL Quest's Welcome Back card knows where you left off, which step the Coach was about to assign, and what skills you've built since last visit. DataLemur saves your solved problems but doesn't pick up your study session — you have to remember what you were doing.
SQL Quest tracks 9 canonical skills (Querying Basics, Aggregation & Grouping, Joins, Subqueries & CTEs, Conditional Logic, Window Functions, String Functions, Date Functions, NULL Handling). Your radar shows weak axes in red — that's what the Coach drills next. DataLemur tags topics on questions but doesn't aggregate into a quantified weakness map.
DataLemur is a list of problems. You decide what to do next. SQL Quest's Coach picks: a 5-min lesson when you're missing a concept · a quick drill when a skill is rusty · a mastery check when you're ready to test up · a placement check when you've drifted. Less decision fatigue. More forward motion.
The same wrong query, on both platforms.
DataLemur (typical)
SQL Quest
This is the difference between grinding problems and building intuition. After 50 problems on SQL Quest, you've internalized why you got each one wrong. After 50 on DataLemur, you've gotten faster at solving them — but the why is in your head only when the gap was obvious.
▶ Try the diagnostic on one query: LEFT JOIN — Keep Everyone Free, about a minute, no signup — the query runs in your browser.
Free tier first. Paid only if you need it.
SQL Quest
Free → $29/mo · $99/yr
Free includes:
226 of 299 challenges — every Easy (93) and Medium (120), plus 6 Hard previews
The Coach: placement check, adaptive next step, 3 goal paths
AI Coach (Claude) — daily quota
Adaptive 9-axis Skillmap
All 3 sector tracks (finance, real estate, manufacturing) — 72 challenges
All 30 company pages
Wrong-answer diagnostic · no signup to start
Pro adds:
AI Coach without the free tier's daily cap
All 74 Hard challenges
Full mock interview bank
All Daily difficulties, full Warm-Up bank, 30-Day Challenge
DataLemur
Free → $15/mo · $60/yr · $300 one-time bundle
Free includes:
A free subset of the question list — the count is not published on the pricing page (checked 2026-09-07)
Browser-based SQL editor
Written solutions on free questions
Premium adds (as listed 2026-09-07):
100+ SQL interview questions from Meta, Google, Amazon
70+ data science interview questions
Bonus video course — yearly and $300 tiers only
$300 bundle: lifetime access to 250+ questions, a 1-hour coaching call with Nick Singh, a signed copy of Ace the Data Science Interview
No AI tutor listed on any tier
DataLemur prices as listed on datalemur.com/pricing on 2026-09-07; SQL Quest prices from the live Pro modal. Both platforms occasionally run promos. DataLemur's monthly is cheaper. SQL Quest's annual is $39 more than DataLemur's and includes the AI Coach — DataLemur's $300 bundle buys the coaching call and the book instead.
Partly. DataLemur has a free tier, but its pricing page does not say how many questions are in it — the question list mixes free and Premium-locked items. Here is what each tier lists, beside SQL Quest's, so you can answer the question for your own case.
DataLemur column as listed on datalemur.com/pricing on 2026-09-07 — re-check before relying on it, tiers change. SQL Quest column from the live challenge bank on 2026-09-06.
So: if your real question is "can I practice SQL interview questions for free without paying?", DataLemur gives you a free sample of its list, and SQL Quest gives you 226 challenges and the Coach at $0 with no account. If it is "which paid tier is the better deal?", DataLemur's $15 monthly is cheaper; SQL Quest's $99 annual is $39 more and includes the AI Coach. See practice SQL with no setup for what the free tier looks like in the browser.
Yes — for the job it was built for. It is a well-made interview question bank with a real pedigree. Whether it is good for you depends on whether you need a bank or a tutor.
Company-attributed questions. The list is tagged by company — Meta, Google, Amazon and others — and the paid tiers list 100+ SQL questions plus 70+ data science questions (as listed 2026-09-07). If you want "the kind of question this company asks", that is the product.
Pedigree. Nick Singh, author of Ace the Data Science Interview, built it after readers asked for an interactive way to practice the book's questions. Written solutions on the questions; a bonus video course on the yearly and lifetime tiers.
A free tier to try before paying, and a $300 bundle that includes a 1-hour coaching call and a signed copy of the book — a human touch no software feature replicates.
Diagnostic feedback. When a query is wrong, SQL Quest tells you which row, column and value differ and why — not "incorrect" plus an expected table to compare by eye. See the example above.
Adaptive next step. The Coach reads a 9-skill Skillmap and picks the lesson, drill or mastery check you need next, across 3 goal paths and 10 lessons. You are not choosing from a flat list.
Price and free depth. 226 of 299 challenges free, Coach included, no signup. Pro is $29/mo · $99/yr against DataLemur's $15/mo · $60/yr · $300 bundle: their monthly is cheaper; our annual is $39 more and includes the AI Coach.
DataLemur if you already know SQL, you are weeks from a named-company interview, you want question volume with company tags, or you are already in Nick Singh's ecosystem.
SQL Quest if you are still learning SQL, you keep getting "incorrect" without knowing why, you want the platform to pick your next step, or you want free depth without an account.
Both if you want maximum coverage — the stack below shows how people combine them, and the five-way comparison covers StrataScratch, LeetCode and HackerRank too.
We're not pretending DataLemur is bad. It's a quality product. Here's when we'd actively recommend it over SQL Quest.
📚 Pick DataLemur if:
You're 1-2 weeks from a Meta, Google, or Amazon onsite and want a cram-bank of questions with verified company provenance — DataLemur sources real interview questions and labels them with high confidence.
You learn well from instructor video. Nick Singh (the Ace the Data Science Interview author) built DataLemur, and its yearly and lifetime tiers include a bonus video course (as listed 2026-09-07) that some learners prefer over text-based AI explanations.
You already know SQL solidly. The wrong-answer diagnostic and AI Coach are most useful when you're stuck. If you're rarely stuck, you mostly want question volume — and DataLemur's curated list is good for that.
You want the 1:1 coaching call and the signed copy of Ace the Data Science Interview that come bundled with DataLemur's $300 lifetime tier (as listed on its pricing page, 2026-09-07). That package has no equivalent here — we don't do coaching calls.
You're already deep into Nick Singh's content (the book, his Twitter/LinkedIn). DataLemur fits cleanly into that ecosystem.
If two of those bullets describe you, DataLemur is probably the right choice. If three of them don't, SQL Quest is probably faster.
Many SQL Quest users keep DataLemur Premium open as their question library. Here's a stack that works:
Foundations on SQL Quest
Run the placement check. Let the Coach drill the foundational skills. Use the AI Coach when you're stuck. Get your Skillmap above 60 on every axis. Roughly 4-6 weeks if you're building from scratch.
Volume on DataLemur
Once your fundamentals are solid, grind DataLemur's company-specific questions. Now you'll be solving them, not staring at "incorrect."
Stuck? Back to SQL Quest's AI Coach
Hit a question on DataLemur you can't crack? Paste it into SQL Quest's AI Coach. Claude reads it cold and walks you through the pattern. Then go back to DataLemur and finish.
Open SQL Quest, write a deliberately wrong query, and see what the wrong-answer diagnostic actually says. No signup. No credit card. Free forever on the core experience.
Try SQL Quest Free ⚡▶ Or start on one question: LEFT JOIN — Keep Everyone
or browse the JOIN challenges →
Other comparisons: vs SQLBolt · vs SQLZoo · vs StrataScratch · vs LeetCode SQL · vs HackerRank SQL · See all 5 →