Skip to main content

JavaScript is required for SkillDojo AI to work properly. Please enable JavaScript and refresh the page.

Skip to content

Home
AI Courses
Quizzes
Developers
Create with AI
Pricing

Home
/
Coding Practice
/
SQL Practice

AI-powered SQL practice

SQL practice problems

Write real queries against fixed, realistic schemas and get instant pass/fail against the expected result — joins, aggregation, subqueries, and window functions.

59problems

4schemas

100%free

Create a problem SQL Tutorial

Search problems

Schemas

Level

Topics

59 of 59 problems

Customers Without OrdersE-commerce — Customers, Orders & Items· subqueryEasy
Active Accounts per CustomerBanking — Card Transactions· joinsEasy
Customer Email and Account Number ListBanking — Card Transactions· joinsEasy
List Cardholders and Their Card NetworksBanking — Card Transactions· joinsEasy
Customer Emails with Active AccountsBanking — Card Transactions· joinsEasy
Employee Department ListHR — Departments & Employees· joinsEasy
Employee Department ListHR — Departments & Employees· joinsEasy
List Employee Names and DepartmentsHR — Departments & Employees· joinsEasy
Headcount per DepartmentHR — Departments & Employees· joinsEasy
Top-Selling Product Categories by CountryE-commerce — Customers, Orders & Items· joinsMedium
Average Salary by Department for Departments with Multiple EmployeesHR — Departments & Employees· joinsMedium
Top Spending Customers by CountryBanking — Card Transactions· cteMedium
Signup Conversion Rate by RegionAnalytics — Daily Metrics· joinsMedium
Monthly Transaction Volume by Account TypeBanking — Card Transactions· date-bucketingMedium
Average Salary by Department (With Minimum Employee Count)HR — Departments & Employees· joinsMedium
Total Spend per Customer by CountryBanking — Card Transactions· joinsMedium
Average Salary by Department with Minimum HeadcountHR — Departments & Employees· joinsMedium
Average Salary by Department with Minimum StaffHR — Departments & Employees· joinsMedium
Top Merchants by Transaction Count per CountryBanking — Card Transactions· joinsMedium
Department Average Salary and HeadcountHR — Departments & Employees· joinsMedium
Regional Signup-to-Order Ratio by DayAnalytics — Daily Metrics· joinsMedium
Average Salary per Department with Minimum StaffHR — Departments & Employees· joinsMedium
Average Salary by Department with Minimum HeadcountHR — Departments & Employees· joinsMedium
Total Spending per Customer by CountryBanking — Card Transactions· aggregationMedium
Total Spending Per Customer in Home CountryBanking — Card Transactions· aggregationMedium
Total Spend Per Customer by CountryBanking — Card Transactions· aggregationMedium
Average Order Value on High Signup DaysAnalytics — Daily Metrics· joinsMedium
Weekly Sales and Signup Summary by RegionAnalytics — Daily Metrics· date-bucketingMedium
Running Total Revenue and Signups by DayAnalytics — Daily Metrics· running-totalMedium
Average Revenue Per Order by Day with High SignupsAnalytics — Daily Metrics· aggregationMedium
Average Revenue per Order for High Signup DaysAnalytics — Daily Metrics· aggregationMedium
Top Customers by Total SpendE-commerce — Customers, Orders & Items· aggregationMedium
Top Customers by Total SpendE-commerce — Customers, Orders & Items· aggregationMedium
Top Customers by Order CountE-commerce — Customers, Orders & Items· joinsMedium
Top-Spending Customers by CountryE-commerce — Customers, Orders & Items· joinsMedium
Average Salary by Manager for Each DepartmentHR — Departments & Employees· aggregationMedium
Average Salary by Department for Departments with At Least 3 EmployeesHR — Departments & Employees· aggregationMedium
Average Revenue per Signup by DayAnalytics — Daily Metrics· joinsMedium
Revenue Performance by Region CategoryAnalytics — Daily Metrics· caseMedium
Department Headcount Including SubordinatesHR — Departments & Employees· recursive-cteMedium
Sales and Signup Conversion Rate by DayAnalytics — Daily Metrics· joinsMedium
Cumulative Revenue and Signups by Day and RegionAnalytics — Daily Metrics· running-totalMedium
Employees With Above-Average Department SalaryHR — Departments & Employees· subqueryMedium
Top Earners Per DepartmentHR — Departments & Employees· windowMedium
Revenue per Customer (Completed Orders)E-commerce — Customers, Orders & Items· aggregationMedium
Departments With More Than Two EmployeesHR — Departments & Employees· aggregationMedium
Top Merchant Per Customer by Transaction ValueBanking — Card Transactions· joinsHard
Find the Missing Days (Gaps & Islands)Analytics — Daily Metrics· gaps-and-islandsHard
Day-over-Day Revenue ChangeAnalytics — Daily Metrics· period-comparisonHard
7-Day Moving AverageAnalytics — Daily Metrics· moving-averageHard
True Running Total With Salary TiesHR — Departments & Employees· windowHard
Top 2 Earners per DepartmentHR — Departments & Employees· top-n-per-groupHard
Salary Ranking With Ties (DENSE_RANK)HR — Departments & Employees· rankingHard
Top Transaction per Card by AmountBanking — Card Transactions· windowHard
Regional Revenue Growth vs. National TrendAnalytics — Daily Metrics· period-comparisonHard
7-Day Moving Average Revenue with Signups ComparisonAnalytics — Daily Metrics· moving-averageHard
Top-Selling Product per Country in 2023E-commerce — Customers, Orders & Items· subqueryHard
Top Three Salaries Per Department With Manager InfoHR — Departments & Employees· windowHard
Top Customer per Product CategoryE-commerce — Customers, Orders & Items· subqueryHard