Practice

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Total0 / 152

Easy0 / 58

Medium0 / 70

Hard0 / 24

SELECT Basics

Easy

1	Employee Name Search Filtering	Easy
2	Employees Earning Over 100K Filtering	Easy
3	Employees Without a Manager Pro Filtering	Easy
4	Low Stock Products Pro Filtering	Easy
5	Orders Above $100 Pro Filtering	Easy
6	Products Out of Stock Pro Filtering	Easy

1	Active Subscriptions NULL	Easy
2	Display Name Fallback Pro NULL	Medium

1	10 Most Recent Orders Sorting	Easy
2	Alphabetical Product Catalog Sorting	Easy
3	Employees Sorted by Department Pro Sorting	Easy
4	Top 5 Highest-Paid Employees Pro Sorting	Easy
5	Top 5 Longest-Tenured Employees Pro Sorting	Easy
6	Top 5 Most Expensive Products Pro Sorting	Easy
7	Customers Ranked by Total Spend Pro Sorting	Medium
8	Products Ranked by Price Within Category Pro Sorting	Medium

1	Average Employee Salary Aggregation	Easy
2	Count Orders by Status Pro Aggregation	Easy
3	Min and Max Salary by Department Pro Aggregation	Easy
4	Minimum and Maximum Order Amount Pro Aggregation	Easy
5	Total Revenue from Orders Aggregation	Easy
6	Total Sales by Region Pro Aggregation	Easy
7	Average Order Value by Customer (Min 3 Orders)Pro Aggregation	Medium
8	Revenue Concentration by Product Pro Aggregation	Medium

1	Average Rating per Product Grouping	Easy
2	Department Headcount Pro Grouping	Easy
3	Find Duplicate Emails Pro Grouping	Easy
4	Highest Paid per Department Pro Grouping	Easy
5	Order Count per Customer Pro Grouping	Easy
6	Product Count per Category Grouping	Easy
7	Top Earning Employees Pro Grouping	Easy
8	Total Items per Order Pro Grouping	Easy
9	User Count by Country Pro Grouping	Easy
10	Average Order Value per Customer Pro Grouping	Medium
11	Employees with Multiple Roles Pro Grouping	Medium
12	First Purchase Date per Customer Pro Grouping	Medium
13	Salary Statistics by Department Pro Grouping	Medium
14	Top 3 Customers by Total Spend Pro Grouping	Medium

1	Active Product Categories Filtering Groups	Easy
2	Customers With Multiple Orders Pro Filtering Groups	Easy
3	High Revenue Products Filtering Groups	Easy
4	Customers With Multiple Orders Pro Filtering Groups	Medium
5	Departments Above Average Salary Pro Filtering Groups	Medium
6	Departments With High Average Salary Pro Filtering Groups	Medium
7	Product Categories With Wide Price Range Pro Filtering Groups	Medium
8	Users With Failed Login Attempts Pro Filtering Groups	Medium

1	Customers With No Orders Joins	Easy
2	Orders with Customer Name Joins	Easy
3	Products Never Ordered Pro Joins	Easy
4	Average Revenue per User (ARPU)Pro Joins	Medium
5	Customer Lifetime Value Pro Joins	Medium
6	Day-1 User Retention Pro Joins	Medium
7	Employees and Their Managers Pro Joins	Medium
8	Full Inventory and Sales Reconciliation Pro Joins	Medium
9	Order Line Items with Customer and Product Pro Joins	Medium
10	Revenue by Product Category Pro Joins	Medium
11	Frequently Bought Together Pro Joins	Hard

1	Products Above Average Price Subqueries	Easy
2	Employees Above Company Average Salary Subqueries	Medium
3	Employees Earning Above Department Average Pro Subqueries	Medium
4	Orders Above the Customer's Own Average Pro Subqueries	Medium
5	Products With No Reviews Pro Subqueries	Medium
6	Second Highest Salary Pro Subqueries	Medium

1	Customer Count by Email Domain String Functions	Easy
2	Extract Username from Email Pro String Functions	Easy
3	Find Long Product Names Pro String Functions	Easy
4	Full Name Formatting String Functions	Easy
5	Normalize Email Addresses Pro String Functions	Easy
6	Clean Phone Numbers Pro String Functions	Medium
7	Extract Domain from URL Pro String Functions	Medium
8	Search Product Descriptions Pro String Functions	Medium

1	Customers Who Signed Up This Year Date Functions	Easy
2	Customers with No Orders in 90 Days Date Functions	Medium
3	Employee Tenure in Years Pro Date Functions	Medium
4	Revenue by Quarter Pro Date Functions	Medium
5	Signup Cohort Size by Month Pro Date Functions	Medium
6	Total Sales by Day of Week Pro Date Functions	Medium
7	Weekly Active Users Pro Date Functions	Medium

1	Orders in a Date Range Date Filtering	Easy
2	Orders Placed in the Last 30 Days Date Filtering	Easy
3	Monthly Revenue Pro Date Filtering	Medium

1	Count Products Ordered More Than Once Distinct	Easy
2	Count Unique Customers Distinct	Easy
3	List Product Categories Pro Distinct	Easy
4	List Unique Customer Countries Pro Distinct	Easy
5	List Unique Job Titles Pro Distinct	Easy
6	Distinct Event Types Per User Pro Distinct	Medium
7	Find Duplicate Email Addresses Pro Distinct	Medium
8	Unique Purchasers by Month Pro Distinct	Medium

1	Average Days Between Orders per Customer Window Functions	Medium
2	Cumulative Revenue by Month Pro Window Functions	Medium
3	Day-over-Day Sales Change Pro Window Functions	Medium
4	Days Between Consecutive Orders per Customer Pro Window Functions	Medium
5	Dense Rank Employees by Salary Pro Window Functions	Medium
6	Month-over-Month Revenue Growth Pro Window Functions	Medium
7	Most Prolific Reviewer per Product Category Pro Window Functions	Medium
8	Most Recent Order per Customer Window Functions	Medium
9	Product Revenue Share Pro Window Functions	Medium
10	Rank Employees by Salary Pro Window Functions	Medium
11	Repeat Purchasers in Consecutive Months Pro Window Functions	Medium
12	Running Total of Sales Pro Window Functions	Medium
13	Salary Percentile Rank Pro Window Functions	Medium
14	Salary Quartile Bands Pro Window Functions	Medium
15	Top 2 Products by Revenue per Category Pro Window Functions	Medium
16	Top Product per Category by Revenue Pro Window Functions	Medium
17	3-Day Moving Average of Sales Pro Window Functions	Hard
18	First and Last Purchase per Customer Pro Window Functions	Hard
19	Last-Touch Marketing Attribution Pro Window Functions	Hard
20	Longest Daily Login Streak per User Pro Window Functions	Hard
21	Median Salary by Department Pro Window Functions	Hard
22	Product Price Change History Pro Window Functions	Hard
23	Rolling 7-Day Revenue Pro Window Functions	Hard
24	Salary Percentile Breakdown Pro Window Functions	Hard
25	Session Gap Analysis Pro Window Functions	Hard
26	Top Driver per City by Completed Rides Pro Window Functions	Hard

1	New vs Returning Customers per Month CTEs	Medium
2	A/B Test Conversion Analysis CTEs	Hard
3	Full Org Chart via Recursive CTE Pro CTEs	Hard
4	Funnel Conversion Analysis Pro CTEs	Hard
5	Longest Monthly Ordering Streak per Customer Pro CTEs	Hard
6	Monthly Recurring Revenue (MRR)Pro CTEs	Hard
7	Reactivated Users Pro CTEs	Hard
8	Revenue by Customer Signup Cohort Pro CTEs	Hard
9	Revenue Rollup by Region and Country Pro CTEs	Hard
10	User Retention by Cohort Pro CTEs	Hard
11	Year-over-Year Revenue Growth Pro CTEs	Hard

1	Employee Performance Rating CASE Expressions	Easy
2	Order Size Label CASE Expressions	Easy
3	Product Availability Status Pro CASE Expressions	Easy
4	Conditional Customer Discount Pro CASE Expressions	Medium
5	Customer Segment Revenue Pro CASE Expressions	Medium
6	Employee Salary Band Classification Pro CASE Expressions	Medium
7	Sales by Quarter Pro CASE Expressions	Medium
8	Pivot Revenue by Quarter Pro CASE Expressions	Hard

1	All Purchases and Refunds Set Operations	Easy
2	Churned Customers Pro Set Operations	Easy
3	Combine Customer Lists Set Operations	Easy
4	Customers Active on Both Channels Pro Set Operations	Easy
5	Combined Employee and Contractor List Pro Set Operations	Medium
6	Multi-Region Product Catalog Pro Set Operations	Medium
7	Products in All Three Stores Pro Set Operations	Medium
8	Subscribers Who Are Not Customers Pro Set Operations	Medium

1	Employee and Manager Name Pairs Self Joins	Easy
2	Find Salary Peers in the Same Department Self Joins	Easy
3	Direct Reports of a Manager Pro Self Joins	Medium
4	Generate Team Matchups Within Division Pro Self Joins	Medium
5	Product Price Pairs Within Category Pro Self Joins	Medium
6	Users With Back-to-Back Login Days Pro Self Joins	Medium
7	Employees Earning More Than Their Manager Pro Self Joins	Hard
8	Products Frequently Bought Together Pro Self Joins	Hard

Org Chart Depth Pro

Recursive CTEs

Medium

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