SQL & DATABASES
Master the language
of data.
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200+
SQL Problems
50+
Database Topics
10+
DBMS Concepts
query_editor.sql
-- Find top performing products
SELECT p.name, SUM(s.quantity) as total_sales
FROM products p
JOIN sales s ON p.id = s.product_id
GROUP BY p.name
ORDER BY total_sales DESC
LIMIT 5;
Query Results (5 rows)
name
total_sales
Premium Widget
12,450
Super Gadget
9,320
Ultra Device
7,890
Medium
Find Second Highest Salary
Write a SQL query to find the second highest salary from the Employee table.
Table: Employee (id, salary)
-- Your solution
SELECT MAX(salary) AS SecondHighest
FROM Employee
WHERE salary < (
SELECT MAX(salary)
FROM Employee
);
Accepted
Runtime: 234ms
SQL Problem Solving
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SELECT & Filtering
EasyJOINs & Subqueries
MediumWindow Functions
HardQuery Optimization
HardDatabase Management Systems
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Storage Engines
Transactions
ACID Properties
Query Optimization
DBMS Architecture
Application Layer
Query Processor
Parser
Optimizer
Executor
Storage Engine
Buffer Pool
Index Manager
Lock Manager
Data Files
Log Files
Index Files
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