MySQL Cheat Sheet.md

MySQL Cheat Sheet

Connecting to MySQL Server

mysql -u [username] -p

Basic MySQL Commands

Show all databases

SHOW DATABASES;

Select a database

USE [database_name];

Show tables in the current database

SHOW TABLES;

Show columns of a table

SHOW COLUMNS FROM [table_name];

Create a new database

CREATE DATABASE [database_name];

Delete a database

DROP DATABASE [database_name];

CRUD Operations

Create a table

CREATE TABLE [table_name] (
  column1 datatype,
  column2 datatype,
  ...
);

Insert data into a table

INSERT INTO [table_name] (column1, column2, ...)
VALUES (value1, value2, ...);

Select data from a table

SELECT column1, column2, ...
FROM [table_name];

Update data in a table

UPDATE [table_name]
SET column1=value1, column2=value2, ...
WHERE [condition];

Delete data from a table

DELETE FROM [table_name]
WHERE [condition];

MySQL Joins

INNER JOIN

SELECT column1, column2, ...
FROM table1
INNER JOIN table2
ON table1.column=table2.column;

LEFT JOIN

SELECT column1, column2, ...
FROM table1
LEFT JOIN table2
ON table1.column=table2.column;

RIGHT JOIN

SELECT column1, column2, ...
FROM table1
RIGHT JOIN table2
ON table1.column=table2.column;

FULL JOIN (not supported in MySQL, can be simulated)

SELECT column1, column2, ...
FROM table1
LEFT JOIN table2
ON table1.column=table2.column
UNION
SELECT column1, column2, ...
FROM table1
RIGHT JOIN table2
ON table1.column=table2.column;

Aggregation Functions

COUNT

SELECT COUNT(column_name)
FROM [table_name]
WHERE [condition];

SUM

SELECT SUM(column_name)
FROM [table_name]
WHERE [condition];

AVG

SELECT AVG(column_name)
FROM [table_name]
WHERE [condition];

MIN

SELECT MIN(column_name)
FROM [table_name]
WHERE [condition];

MAX

SELECT MAX(column_name)
FROM [table_name]
WHERE [condition];

This cheat sheet provides a quick reference for someone new to MySQL, covering basic commands, CRUD operations, joins, and aggregation functions.