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97 exercises

mediumSQL
Employee Salary Ranking with Window Functions
Write SQL queries using window functions to analyze employee salary data within departments. You have access to an `emp...
sqlwindow-functions
ranking
+5
mediumSQL
Recursive CTE for Employee Manager Chain
Create a SQL query using Common Table Expressions (CTEs) to build a complete organizational hierarchy showing the chain...
sqlrecursive-ctehierarchy+5
mediumSQL
Finding Highest-Paid Employee by Department
Write a SQL query that joins three tables to find the highest-paid employee in each department. You have three tables:...
sqljoinswindow-functions+4
easySQL
Finding High-Volume Customers
Write a SQL query to identify customers who have placed more than 3 orders. You'll work with two tables: - `customers`:...
sqljoinsgroup-by+4
easySQL
SQL Filtering and Ordering - Employee Query
Write a SQL query to find employees in the Engineering department who were hired after January 1st, 2023. ## Requiremen...
sqlfilteringordering+5
hardTypeScript
Express Error Handling Middleware System
Build a comprehensive error handling middleware system for Express that catches different types of errors and returns co...
expressmiddlewareerror-handling+6
mediumTypeScript
Product API with Pagination, Filtering, and Sorting
Build a RESTful API handler for a GET /products endpoint that supports advanced query features. ## Requirements Implem...
apipaginationfiltering+5
mediumTypeScript
Rate Limiter Middleware
Build a rate limiter middleware that tracks requests per IP address and enforces a limit of 10 requests per minute. ##...
rate-limitingmiddlewaretypescript+6
mediumTypeScript
User Management API with CRUD Operations
Build a complete user management system with CRUD endpoints for a `/users` resource using in-memory storage. ## Require...
crudapivalidation+6
mediumTypeScript
Express Middleware Chain: Logging and Authentication
Build two Express middleware functions and combine them into a working application: ## Request Logger Middleware Create...
expressmiddlewareauthentication+5
easyTypeScript
Basic Express Server with Health and Echo Endpoints
Create an Express server with two endpoints: 1. **GET /health** - Returns a JSON object with status 'ok' 2. **POST /ech...
expressrest-apiendpoints+5
mediumPython
Merge Overlapping Intervals
Write a function that merges overlapping intervals and returns the result sorted by start time. ## Requirements Implem...
intervalssortingarray-manipulation+2
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