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DataLemur alternatives: SQL interview practice sites compared
DataLemur is a good product at a low price. People look for alternatives for one of four reasons: they want more questions, a bigger free tier, Python or ML practice alongside SQL, or feedback on why a query is wrong. The table says which alternative answers which.
Who wrote this: the team that builds SQL Quest, which is one of the alternatives below. Every price, free tier and question count for another site was read off that site's own page on 2026-09-13 and is linked beside it. Where a site did not state something, this page says so rather than guessing.
DataLemur in one paragraph
Company-attributed SQL interview questions with hints and written solutions, from the author of Ace the Data Science Interview, at the lowest monthly price here. Pricing on 2026-09-13: $15/month, $60/year, or $300 one-time (coaching call, signed book, lifetime access). Free: Free questions and a free SQL tutorial; the number of free questions is not stated. Engines: PostgreSQL 14, MySQL. Source.
What it does well: The cheapest paid interview-practice plan on this page; Python, statistics and ML questions as well as SQL; Both PostgreSQL and MySQL in the editor; Discussion and submissions tabs on each question.
Pick by what you need
The alternatives side by side
| Site | Free tier | Paid (checked 2026-09-13) | Question bank, in the site's words | SQL engines |
|---|---|---|---|---|
| DataLemur | Free questions and a free SQL tutorial; the number of free questions is not stated | $15/month, $60/year, or $300 one-time (coaching call, signed book, lifetime access) | "100+ SQL Interview questions" on the monthly and yearly plans; "250+ interview questions" with lifetime access | PostgreSQL 14, MySQL |
| StrataScratch | Free plan with "75+" coding questions (all languages), free SQL and Python learning paths, "No credit card required" | $19/month; $97.30/year or $202.30 lifetime on a 30%-off promotion running on the day (list $139 and $289); 5-day money-back guarantee | "1000+ coding questions (SQL, Python, R)"; "500+ ML, stats, system design questions" | Postgres, MySQL, MSSQL, Oracle (plus Pandas, Polars, PySpark, R) |
| LeetCode (SQL 50 and Database set) | The SQL 50 study plan ("50 essential SQL questions", every one free when we checked) and part of the Database set; running code needs an account | Premium $35/month or $159/year ("Prices are marked in USD") | "50 essential SQL questions" in SQL 50, "Basic to intermediate SQL topics"; a larger Database problem set, much of it Premium | MySQL, MS SQL Server, PostgreSQL, Oracle (plus Pandas) |
| SQL Quest | 226 of 299 questions (every Easy and Medium plus the Hard previews) run free in the browser with no signup; the Coach, the Skillmap and a daily AI tutor allowance are free | Pro $29/month or $99/year | 299 SQL questions; company practice sets on 30 company pages | SQLite, in the browser |
| HackerRank (SQL track) | Free with an account ("Create a free account") | No candidate price on the practice pages | Subdomains from Basic Select to Advanced Join; no total stated on the page | MySQL, Oracle, T-SQL, DB2 |
| Analyst Builder | Free plan, "$0 forever", "no card needed", with free questions and explanation videos | $34/month or $249/year | "200+ Practice questions built to mirror the real job" ("100+ technical", "100+ general") | MySQL, PostgreSQL, MSSQL (plus Python, R) |
| SQLPad | A sample question runs without logging in ("You can practice this sample without logging in"); most of the list is locked | SQL & R plan $99/month, or $79/month on quarterly billing; one-time annual pass $599 | "230+ Interview-style coding questions"; "23+ Company-focused question sets" | Postgres, MySQL (plus Python, R) |
| Interview Query | "Take the data science challenge for free!"; free-tier contents not stated | Not shown when we checked — the pricing page did not render prices | "1000+ authentic questions" on the pricing page, "500+ real questions" on the homepage | Not stated |
| SQLBolt, SQLZoo and PostgreSQL Exercises | No price, paywall or signup shown on any of the three | None shown | SQLBolt: lessons 1–18 with an exercise each; SQLZoo: numbered tutorials plus assessments of "15 questions graded easy, medium and hard"; PostgreSQL Exercises: one dataset from simple selects to recursive queries | SQLBolt and SQLZoo: not stated for the in-browser engine; PostgreSQL Exercises: real PostgreSQL |
Prices were seen from a connection outside the US; LeetCode states its prices are in USD, the others show $ without naming a currency. Promotions running on the day are labelled.
Each alternative, honestly
StrataScratch
Best for: Data science, ML and AI engineering candidates who want SQL and Python alongside concept questions, take-home projects and AI mock interviews.
- The largest coding bank of the SQL-first tools here
- The widest dialect choice: four SQL engines plus Pandas, Polars, PySpark and R
- User solutions and community discussion
- A lifetime option and a 5-day refund
Look elsewhere if you only need SQL and want most of the practice free — the free plan is "75+" questions across every language.
Source: platform.stratascratch.com/pricing, checked 2026-09-13.
LeetCode (SQL 50 and Database set)
Best for: People already using LeetCode for coding interviews who want a free, structured 50-question SQL plan in the same place.
- SQL 50 costs nothing
- Four SQL dialects
- A very large community and discussion on every problem
- Company tags and timed interview simulations with Premium
Look elsewhere if you want explanations of why a query is wrong, or practice beyond basic-to-intermediate without Premium.
Source: leetcode.com/subscribe/, checked 2026-09-13.
SQL Quest — ours
Best for: SQL interview practice that finds your weakest skill — a Skillmap across nine SQL skills — and builds the next question around it, with a diagnosis of which rows a wrong answer got wrong.
- A free tier of 226 questions that needs no account
- Wrong answers are diagnosed, not just marked
- Practice ordered by your weakest skill
- A free readiness test and free query tools
Where it is weaker:
- A smaller bank than StrataScratch, LeetCode or DataInterview
- SQL only: no Python, R or ML questions
- One dialect (SQLite), where others offer four
- A younger product with a smaller community
Look elsewhere if you need Python or ML prep, or to practise in a specific dialect such as SQL Server or Oracle.
Our figures are counted from the question bank when this page is built.
HackerRank (SQL track)
Best for: Free, short graded SQL exercises, skill certificates, and practice on the platform many employers use for screening.
- Free to practise
- Four engines including Oracle and DB2
- Certification
- The same platform many screens run on
Look elsewhere if you are past the basics and want interview-shaped analytics questions rather than short exercises.
Source: www.hackerrank.com/, checked 2026-09-13.
Analyst Builder
Best for: Aspiring data analysts who want courses (SQL, Excel, Tableau, Power BI, Python) and practice questions on one subscription.
- A permanent free plan
- A video explanation for each question
- Three SQL dialects
- Full courses beyond SQL
Look elsewhere if you want to drill SQL interview questions specifically rather than learn the analyst toolkit.
Source: www.analystbuilder.com/pricing, checked 2026-09-13.
SQLPad
Best for: SQL plus R and Python practice with company-focused sets, for people comfortable with a course-style price.
- You can run SQL before creating an account
- R support, which is rare
- Company-focused sets
- A one-time annual pass
Look elsewhere if price matters — it is the most expensive SQL plan on this page.
Source: sqlpad.io/pricing/, checked 2026-09-13.
Interview Query
Best for: Data science candidates who want SQL next to product sense, statistics, ML, take-homes and company interview guides.
- Broad data-science coverage beyond SQL
- Company interview guides
- Take-home challenges
- Peer mock interviews, an AI interviewer and human coaching
Look elsewhere if you need a clear price before signing up, or SQL-only depth.
Source: www.interviewquery.com/pricing, checked 2026-09-13.
SQLBolt, SQLZoo and PostgreSQL Exercises
Best for: Learning SQL from zero, before interview practice makes sense.
- No account and no cost
- The gentlest on-ramp on this page
- PostgreSQL Exercises runs real Postgres under an open licence
Look elsewhere if you already know SQL and are preparing for an interview.
Source: pgexercises.com/, checked 2026-09-13.
Not sure what you need yet?
Ten questions, no signup: a Skillmap across joins, window functions, aggregation and the rest, and the one skill to fix first — whichever site you practise on afterwards.
Check my interview readinessQuestions
What is the best free alternative to DataLemur?
For a structured free plan, LeetCode's SQL 50 (it needs an account to run code). For the largest free tier that needs no account, SQL Quest: 226 of its 299 questions run free in the browser. For learning from zero, SQLBolt or SQLZoo.
Is there an alternative to DataLemur with Python questions?
StrataScratch has the largest Python bank alongside SQL. SQLPad, Analyst Builder and Interview Query also cover Python, according to their own pages. SQL Quest is SQL only.
How were these prices checked?
Each price and free tier was read off the vendor's own pricing page on 2026-09-13, and the page is linked under each tool. Prices change and some sites localise them, so check the vendor's page before you pay. Promotions running on the day are labelled as promotions.
Who wrote this comparison?
The team that builds SQL Quest, which is one of the alternatives listed. That is why the SQL Quest section lists what it is worse at, and why no competitor fact on this page is from memory.