Create MySQL Notes

MySQL Notes

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+*MySQL Bootcamp*
+
+**Lesson Objectives**
+1. What is a DB
+1. What are the different ways to store data
+1. Why do we need SQL
+1. Diagram MySQL structure
+1. Connect to MySQL
+1. Create a DB
+1. CRUD
+1. ALTER
+1. LIKE
+1. AND/OR
+1. DISTINCT
+1. OFFEST/LIMIT
+1. ORDER BY
+1. GROUP BY
+
+```mysql
+SHOW DATABASES;
+CREATE DATABASE users;
+USE users;
+CREATE TABLE employees (NAME VARCHAR(20), age INT);
+DESCRIBE employees;
+
+INSERT INTO employees (NAME, age) VALUES ('Matt' , 34);
+
+SELECT * FROM employees;
+SELECT age FROM employees;
+
+SELECT * FROM employees WHERE NAME = "Charlie" OR age = 80;
+SELECT * FROM employees WHERE age > 45;
+SELECT * FROM employees WHERE age != 63;
+
+UPDATE employees SET weight = 300 WHERE NAME = 'Bill' LIMIT 1;
+UPDATE employees SET dob = NOW() WHERE id = 9;
+UPDATE employees SET dob = '2015-06-26 12:04:10' WHERE id = 10;
+
+DELETE FROM employees WHERE NAME = "Bill" AND age = 10;
+
+SELECT * FROM employees ORDER BY age DESC;
+SELECT * FROM employees ORDER BY age ASC LIMIT 2;
+SELECT * FROM employees ORDER BY age ASC LIMIT 2 OFFSET 1;
+SELECT * FROM employees ORDER BY age DESC, NAME ASC;
+
+ALTER TABLE employees ADD COLUMN weight FLOAT;
+ALTER TABLE employees DROP COLUMN height;
+ALTER TABLE employees ADD COLUMN height FLOAT AFTER NAME;
+ALTER TABLE employees MODIFY COLUMN height FLOAT AFTER age;
+ALTER TABLE employees ADD COLUMN id INT FIRST;
+ALTER TABLE employees ADD COLUMN dob DATETIME;
+ALTER TABLE employees CHANGE dob date_of_birth DATETIME;
+ALTER TABLE companies ADD COLUMN id INT NOT NULL AUTO_INCREMENT PRIMARY KEY FIRST;
+
+SELECT COUNT(*), age FROM employees GROUP BY age;
+SELECT COUNT(*) FROM employees GROUP BY age;
+SELECT SUM(age) FROM employees GROUP BY age;
+SELECT AVG(age) FROM employees;
+SELECT MIN(age) FROM employees;
+SELECT MAX(age) FROM employees;
+SELECT GROUP_CONCAT(age) FROM employees;
+
+SELECT * from employees FULL JOIN companies;
+SELECT * FROM employees JOIN companies ON employees.`employer_id` = companies.`id`;
+SELECT * FROM employees RIGHT OUTER JOIN companies ON employees.`employer_id` = companies.id WHERE employees.`employer_id` IS NULL;
+SELECT * FROM employees LEFT OUTER JOIN companies ON employees.`employer_id` = companies.id WHERE employees.`employer_id` IS NULL;
+SELECT employees.*, companies.`name` FROM employees INNER JOIN companies ON employees.`employer_id` = companies.id;
+SELECT e.*, c.name AS company_name FROM employees AS e INNER JOIN companies AS c ON e.employer_id = c.id;
+```