Problems
Practice real interview questions for SQL, Python, Pandas, NumPy, Excel, Power BI and Statistics.
Find Top Customers
GROUP BYJOINORDER BY
SQL
Easy
82%
12K
Customers From a City
SELECTWHEREORDER BY
SQL
Easy
89%
15K
Customers and Their Order Counts
JOINGROUP BYAggregation
SQL
Medium
61%
8.3K
Calculate Monthly Revenue
GROUP BYDateAggregation
SQL
Medium
58%
8K
Second Highest Salary
SubqueryAggregation
SQL
Medium
47%
9.6K
Average Salary by Department
GROUP BYAggregation
SQL
Easy
85%
11K
Products Never Ordered
SubqueryJOINDISTINCT
SQL
Medium
63%
7.1K
Employees Earning More Than Their Manager
Self JoinJOIN
SQL
Medium
54%
6.8K
Top Product Category by Sales
JOINGROUP BYAggregation
SQL
Medium
57%
5.9K
Running Total of Revenue
Window FunctionsDateAggregation
SQL
Hard
33%
3.4K
Each Customer's First Order
Window FunctionsCTE
SQL
Hard
36%
3.1K
Repeat Customer Retention
CTEHAVINGAggregation
SQL
Hard
24%
2.3K
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