SQL Skills for Your Resume: The Levels, the Jobs, and How to Prove Yours

SQL skills are the commands and clauses that you use to get, change and check data in a database. In our view, the main SQL skills are SELECT, WHERE, JOIN, GROUP BY, subqueries, CTEs and window functions, in three levels: basic, intermediate and advanced.

We make SQLMaxx Learn, a free SQL course, so we are not neutral on these questions.

We put SQL skills in three levels, in the order that you learn them: basic, intermediate and advanced. The levels are our own grouping, and they follow the 5 tiers of the 66 lessons in SQLMaxx Learn. On O*NET OnLine, SQL is one skill, with no levels.

With basic SQL skills, you get data from one table. You select columns with SELECT, filter rows with WHERE, and sort rows with ORDER BY. You remove duplicate rows with DISTINCT. These skills are in the 12 lessons of tier 1 of SQLMaxx Learn.

With intermediate SQL skills, you answer questions about groups of rows and about two or more tables. You count and add with aggregate functions and GROUP BY. You combine tables with joins. You put one query inside a different query, as a subquery. These skills are in the 15 lessons of tier 2 of SQLMaxx Learn.

With advanced SQL skills, you write a long query in named steps, and you calculate across rows. You name each step with a CTE, a WITH clause. You calculate ranks, running totals and shares with window functions and OVER.

At this level, you also read a query plan and find the cause of a wrong result. The skills check below does not test these two skills. These skills are in the 39 lessons of tiers 3 to 5 of SQLMaxx Learn.

In the check, you query the conversions table of Streamhub, a made-up software company. Each row is one purchase of a plan by one user. There are 60 rows and 3 plans. For task 2, you also need the users table, with the country of each user.

With this query, you get the number of conversions and the revenue of each plan:

In the Streamhub data, the enterprise plan has fewer conversions than the pro plan, but it has the most revenue. Now do the three tasks below in the editor. Each task is at one level. Try each task before you open its answer.

1. Basic: show each plan and its amount one time, with the largest amount first.
   Show the answer to task 1

   SELECT DISTINCT plan, amount
   FROM conversions
   ORDER BY amount DESC;

   plan	amount
   enterprise	499.00
   pro	49.00
   starter	9.00

   You get 3 rows, so in the Streamhub data, each plan has one price.

2. Intermediate: show the conversions and the revenue of each country. Join conversions to users on the user id.
   Show the answer to task 2

   SELECT u.country, COUNT(*) AS conversions, SUM(c.amount) AS revenue
   FROM conversions AS c
   JOIN users AS u ON u.id = c.user_id
   GROUP BY u.country
   ORDER BY revenue DESC, u.country;

   country	conversions	revenue
   AU	8	2152.00
   US	14	1916.00
   GB	10	1230.00
   DE	8	1172.00
   CA	8	682.00
   FR	8	682.00
   JP	2	548.00
   KR	2	58.00

   You get 8 rows. In the Streamhub data, AU has the most revenue, but US has the most conversions. Two countries have the same revenue, so you also sort by country, as the second sort.

3. Advanced: add a column with the share of the total revenue for each plan, as a percent with one decimal place.
   Show the answer to task 3

   SELECT plan, SUM(amount) AS revenue,
     ROUND(100 * SUM(amount) / SUM(SUM(amount)) OVER (), 1) AS revenue_pct
   FROM conversions
   GROUP BY plan
   ORDER BY revenue DESC;

   plan	revenue	revenue_pct
   enterprise	6986.00	82.8
   pro	1274.00	15.1
   starter	180.00	2.1

   With the window function SUM(SUM(amount)) OVER (), you get the total of all plans on each row. In the Streamhub data, the enterprise plan has 82.8 percent of the revenue.

Put a skill on your resume only when you can do its task with no help. If you cannot do task 2 yet, start with the lesson on INNER JOIN.

When you put SQL on a resume, show the employer your level. Do these four steps:

1. Write SQL in your skills section, with the database product that you used, for example PostgreSQL.
2. Write the SQL skills at your level, for example joins, GROUP BY and window functions. If you write only "SQL", the employer cannot see your level.
3. For each project, write one line with the question, the SQL skill and the result.
4. Write only the SQL skills that you can show in an interview.

These steps are our view. Use the words of the job post where they are true for you.

Here are three example resume lines. Write a line like these only for work that you did:

• Skills section: "SQL (PostgreSQL): joins, GROUP BY, subqueries, CTEs, window functions".
• Job: "Wrote SQL queries with joins and GROUP BY to report weekly sales by region."
• Project: "Used SQL window functions on public transit data to find the busiest stations each month."

Jobs that use SQL are in data, in software and in business fields. O*NET OnLine is the website of the occupation database that the U.S. Department of Labor sponsors (O*NET OnLine Help: O*NET Overview). As of October 2026, it gives SQL the label "Hot Technology" for 151 occupations (O*NET OnLine, Hot Technologies: Structured query language SQL). O*NET says: "Hot Technologies are requirements frequently included in employer job postings" (O*NET OnLine, Technology Skills: Database Administrators).

Below are 11 of the 151 occupations. We chose them to show data, software, finance, marketing, accounting and security work.

For 8 of the 11 occupations in the list on this page, SQL is also "In Demand" for that occupation. The O*NET definition of "In Demand" is: "In Demand skills are frequently included in employer job postings for this occupation." The text after each name is our description of the SQL work, not the O*NET text.

• Database Administrators (In-Demand Hot Technology): they keep a database safe, fast and available, and control who can read and change the data.
• Data Warehousing Specialists (In-Demand Hot Technology): they build the tables that other people query, and load new data into them.
• Business Intelligence Analysts (In-Demand Hot Technology): they write the queries behind reports and dashboards.
• Data Scientists (In-Demand Hot Technology): they get and prepare the data before they build a model.
• Software Developers (In-Demand Hot Technology): they write the SQL that an application uses to read and save its data.
• Software Quality Assurance Analysts and Testers (In-Demand Hot Technology): they query the database to make sure that an application saved the correct data.
• Web Developers (In-Demand Hot Technology): they read and save the data of a website, for example user accounts and orders.
• Financial and Investment Analysts (In-Demand Hot Technology): they get prices, transactions and financial results for their analysis.
• Market Research Analysts and Marketing Specialists (Hot Technology): they count customers, campaigns and conversions.
• Accountants and Auditors (Hot Technology): they select the transactions to test, and compare the records of two systems.
• Information Security Analysts (Hot Technology): they search logs and records for signs of an attack.

In our view, an information security analyst must also know SQL injection. In this attack, a person puts SQL "via the input data from the client to the application" (OWASP, SQL Injection). With a successful attack, the person can "read sensitive data from the database".

When you search for jobs with SQL, you find many different job titles. Compare each job post with these occupations. Then read which SQL tasks the post names.

A related question is “can I get a job if I learn SQL?”. In our view, the answer depends on the job and on what else you can show. We think that each of the jobs on this page also needs other skills, for example the tools of the field and a knowledge of its data.

For analyst work, see our guide to SQL in data analysis, with real analyst queries.

SQL experience is not only paid work. You can get SQL experience in three ways:

• Do a project on public data, and write down the questions that your queries answer.
• Solve practice problems where you get a check of your result.
• Find a task in your current job where a query can replace a manual step.

In our view, a project is the best experience for a resume, because an employer can read the queries. We think that good SQL practice projects answer a real question with public data.

With a SQL certificate, you show that you finished a course or passed a test. You do not show how you write a query today. In our view, a certificate helps most when an employer can check it, and when your resume also names a project.

In our guide, we put SQL certificates in three kinds: proctored exams, tests and course certificates. We answer the question “is there a SQL certification?” with a ranked list of all three kinds. For a certificate at no cost, see our list of where to learn SQL online free with certificate. We also make a free course with a certificate: see how our SQL course online with certificate works.

In some SQL interviews, you get a live task: you write a query while the interviewer watches. For this type of task, we suggest these steps:

1. Read the question.
2. Say which tables and columns you need.
3. Write the query in small steps.
4. Run each step.
5. Check the result with a number that you know, for example a row count.
6. Explain each part of the query to the interviewer.

We also think that the best SQL practice for interviews is a problem that you have not seen before, with a time limit.

Yes. On O*NET OnLine, SQL is a Hot Technology for occupations in data, in software and in business (see the list above). The limit, in our view: SQL is one skill of a job, not the full job.

If your question is “is SQL outdated?”, start with the job data. We compare the studies of SQL in job posts and show where their results are different.

In SQLMaxx Learn, you start with SELECT and continue to the last tier, "Expert". On our course page, you can learn SQL hands-on in 66 lessons, in order. Lesson 1 is "SELECT and Column Expressions". You can start it in your browser with no account.

You write each query in a real PostgreSQL database and press "Check answer", but you learn only PostgreSQL and see no video.