Our notes on DataLemur

We wrote these notes when we read the DataLemur site for our SQL comparisons. For each note, you see the day of our check and a link to the page that we read.

We give the label "Product's own words" to a note that holds only what DataLemur says about its own product.

DataLemur price and plans

DataLemur sells Premium access to "100+ SQL Interview questions" with hints and full solutions. Product's own words Checked October 23, 2026 (source)
The SQL tutorial is free. DataLemur charges $15 monthly or $60 yearly for Premium. Checked October 23, 2026 (source)

DataLemur free use

You can read every lesson of the SQL tutorial free. In the lessons, we found 46 different practice problems. With no account, you can open 45 of them. One is marked "DataLemur Premium Only". Checked October 23, 2026 (source)
In the free SQL tutorial, there are 14 practice problems in the lessons on GROUP BY, joins, CTEs and subqueries, and window functions. You can open all 14 with no account. Examples are "Easy SQL GROUP BY Practice Exercise" in lesson 203 (GROUP BY) and "Cities With Completed Trades" in lesson 211 (joins). Another example is "Supercloud Customer" in lesson 302 (CTEs and subqueries). Other examples are "Card Launch Success" in lesson 303 (window functions) and "Top 5 Artists" in lesson 304 (ranking functions). We also found "Y-on-Y Growth Rate" in lesson 305 (LEAD and LAG). We found no Premium mark on these problems. To use Submit, the answer check, you must sign in. Checked October 30, 2026 (source)

DataLemur account

You need no account to read lessons and run code. You must sign in to use Submit, the answer check. Checked October 20, 2026 (source)
With a free account, we ran the two-query test with Submit on the free question "Histogram of Tweets" (Easy). The task asks for no order. With Run Code, you see the output, but DataLemur does not check it. For the correct rows in a different order (ORDER BY tweet_bucket DESC), DataLemur showed "Mismatched" and "Your query's output doesn't match with the solution's output!", with our output, the expected output and the status "Error". For one row too few, DataLemur showed the same words. The same query with the rows in ascending order got "Accepted". Checked November 1, 2026 (source)
In its official solution to "Histogram of Tweets", DataLemur writes no ORDER BY clause. With Submit, DataLemur accepted the rows only in ascending order. Checked November 1, 2026 (source)

DataLemur query check and help

With no account, you can run your query and see the output, but you must sign in to use Submit. Checked October 20, 2026 (source)
In its SQL tutorial, DataLemur says: "if you login, you can submit your solution which we'll grade for correctness!" We ran the two-query test with Submit, with a free account. DataLemur showed "Mismatched" for the correct rows in a different order and for one row too few. DataLemur accepted the rows only in ascending order, although DataLemur writes no ORDER BY clause in its official solution. Checked November 1, 2026 (source)

DataLemur SQL topics

DataLemur has tutorial lessons on GROUP BY, joins, CTEs, subqueries, window functions, LEAD and LAG, and self joins. Checked October 23, 2026 (source)
On the SQL question list, you can filter by 22 topic tags. Examples are Aggregate Functions, Joins, Common Table Expressions (CTE) or Subquery, Window Functions, and Date-Time Functions. The tag counts are more than the 54 questions that you see with no account. For this reason, we cannot tell the topics of those 54 questions. Checked October 23, 2026 (source)
Lesson 203 is on GROUP BY. In lesson 211, you learn INNER JOIN, LEFT JOIN, RIGHT JOIN and FULL OUTER JOIN. Checked October 15, 2026 (source)
In lesson 212, you learn EXTRACT, DATE_PART, DATE_TRUNC and INTERVAL. Checked October 15, 2026 (source)
In the lesson on LEAD and LAG for time-series data, you practice a Wayfair question, "Y-on-Y Growth Rate", on the year-on-year growth rate of the total spend of each product. You can open this question free with no account. Checked October 17, 2026 (source)
DataLemur has tutorial lessons on CTEs and subqueries (302), window functions (303), ranking (304), and LEAD and LAG (305). Checked October 15, 2026 (source)

DataLemur SQL engines

You write practice queries in PostgreSQL 14. On some DataLemur questions, you can also choose MySQL. Checked October 30, 2026 (source)
With no account, we checked the 54 SQL questions in the DataLemur question list and the 46 practice problems in its SQL tutorial. On 23 of the 54 questions and 8 of the 46 problems, you can also choose MySQL. The 8 problems are among the 23 questions. On "Page With No Likes" and "Card Launch Success", we chose MySQL in the engine menu, and DataLemur ran our query in MySQL 8.0.45. On a question without MySQL, for example the GROUP BY practice exercise, DataLemur shows "MySQL (coming soon⏳)" in the menu. We could not choose it. Checked October 24, 2026 (source)

DataLemur content and size

33 lessons in three levels: Basic, Intermediate, and Advanced. Checked October 23, 2026 (source)
With no account, DataLemur shows 54 SQL questions in its question list, and DataLemur shows no Premium mark on them. DataLemur does not list its Premium SQL questions there. For example, "Ad Campaign ROAS" is a Premium question, and it is not in the list. DataLemur also does not list the 4 SQL questions that we found with a referral task. On these questions, DataLemur shows "To view this question you must complete referral task". Checked October 30, 2026 (source)
DataLemur names the tutorial "Free SQL Tutorial for Data Analysts & Data Scientists". Checked October 15, 2026 (source)
DataLemur has tutorial lessons on NULL values (209), CASE (210) and string functions (311): "Use string functions to clean text data." Checked October 15, 2026 (source)
In lesson 312, a case study, you analyze Instacart grocery order data in 5 tables, in the role of a data analyst at Instacart. Checked October 15, 2026 (source)
DataLemur does not publish a full count of its SQL questions. DataLemur says "100+ SQL Interview questions" for Premium. On October 20, 2026, with no account, we found and opened 139 different DataLemur SQL question pages. Of these, 89 are free, 46 need Premium, and 4 need a referral task. We found the pages through the DataLemur question list, its SQL tutorial and public lists of its page addresses. For this reason, DataLemur can have SQL questions that we did not find. Checked October 30, 2026 (source)
With no account, we opened the 33 lessons of the DataLemur SQL tutorial in a browser. In the 33 lessons, we found no video player, no video frame and no link to YouTube or Vimeo. Each lesson is text. In 31 of the 33 lessons, DataLemur gives SQL code examples. In 28 of the 33 lessons, DataLemur links to one or more of its SQL questions. Checked October 23, 2026 (source)

DataLemur certificate

We found no certificate on the tutorial pages. Checked October 23, 2026 (source)

DataLemur updates

DataLemur strengths and limits

DataLemur links its lessons to real SQL interview questions from companies such as Amazon and Microsoft. Checked October 12, 2026 (source)
In its SQL SELECT lesson, DataLemur links to practice questions with company names. For example, DataLemur links to an "Amazon SQL Interview Question" and a "Microsoft SQL SELECT Practice Exercise". Checked October 24, 2026 (source)
Without an account, you can run your query, but you get no check against the answer. Checked October 20, 2026 (source)