📝 SQL Cheatsheet
A quick reference guide for SQL programming — perfect for beginners and interview revision 📊
This SQL cheatsheet helps you quickly recall commonly used SQL commands for
database creation, querying, data manipulation, and performance optimization.
1️⃣ Database Basics
CREATE DATABASE db_name;
USE db_name;2️⃣ Tables
-- Create table
CREATE TABLE table_name (
col1 datatype,
col2 datatype
);
-- Drop table
DROP TABLE table_name;
-- Alter table
ALTER TABLE table_name
ADD column_name datatype;3️⃣ Insert Data
INSERT INTO table_name (col1, col2)
VALUES (val1, val2);4️⃣ Select Queries
-- Select all columns
SELECT * FROM table_name;
-- Select specific columns
SELECT col1, col2 FROM table_name;
-- Select with condition
SELECT *
FROM table_name
WHERE condition;5️⃣ Update Data
UPDATE table_name
SET col1 = value1
WHERE condition;6️⃣ Delete Data
DELETE FROM table_name
WHERE condition;7️⃣ Joins
-- Inner Join
SELECT *
FROM table1
INNER JOIN table2
ON table1.col = table2.col;
-- Left Join
SELECT *
FROM table1
LEFT JOIN table2
ON table1.col = table2.col;
-- Right Join
SELECT *
FROM table1
RIGHT JOIN table2
ON table1.col = table2.col;8️⃣ Aggregations
-- Count rows
SELECT COUNT(*) FROM table_name;
-- Sum values
SELECT SUM(col) FROM table_name;
-- Group by
SELECT col, COUNT(*)
FROM table_name
GROUP BY col;9️⃣ Sorting & Limiting
-- Order results
SELECT *
FROM table_name
ORDER BY col ASC; -- or DESC
-- Limit results
SELECT *
FROM table_name
LIMIT n;🔟 Indexes
-- Create index
CREATE INDEX idx_name
ON table_name (col);
-- Drop index
DROP INDEX idx_name;1️⃣1️⃣ Subqueries
SELECT *
FROM table_name
WHERE col IN (
SELECT col FROM other_table
);1️⃣2️⃣ Views
-- Create view
CREATE VIEW view_name AS
SELECT * FROM table_name;
-- Drop view
DROP VIEW view_name;
💡 Tip: Bookmark this cheatsheet for quick SQL revision before interviews or coding sessions!
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