Interactive SQL Environment for Learning & Testing
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📜 Query History
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Execute a query to see results...
🔍 Query Execution Plan
🎓 SQL Tutorial
📚 SQL Basics
Learn the fundamentals of SQL queries:
SELECT: Retrieve data from tables
WHERE: Filter rows based on conditions
ORDER BY: Sort results
LIMIT: Limit number of results
SELECT name, email FROM customers WHERE country = 'USA' ORDER BY name LIMIT 10;
🔗 SQL Joins
Combine data from multiple tables:
INNER JOIN: Matching records from both tables
LEFT JOIN: All records from left table
RIGHT JOIN: All records from right table
FULL JOIN: All records from both tables
SELECT c.name, o.total FROM customers c INNER JOIN orders o ON c.id = o.customer_id;
⚡ SQL Functions
Use built-in functions for data manipulation:
COUNT, SUM, AVG: Aggregate functions
UPPER, LOWER: String functions
DATE functions: Date manipulation
CASE WHEN: Conditional logic
SELECT COUNT(*) as total_customers, AVG(age) as avg_age FROM customers;
🚀 Advanced SQL
Complex queries and optimizations:
Subqueries: Nested SELECT statements
Window Functions: ROW_NUMBER, RANK, etc.
CTEs: Common Table Expressions
Indexes: Performance optimization
WITH top_customers AS (SELECT customer_id, SUM(total) as spent FROM orders GROUP BY customer_id) SELECT * FROM top_customers ORDER BY spent DESC LIMIT 5;