Update MySQLNotes.md

MySQLNotes.md

@@ -22,60 +22,60 @@
 SHOW DATABASES;
 CREATE DATABASE our_database_name;
 USE our_database_name;
-CREATE TABLE employees (first_name VARCHAR(20), age INT);
-DESCRIBE employees;
+CREATE TABLE people (first_name VARCHAR(20), age INT);
+DESCRIBE people;
 
 -- CRUD
-INSERT INTO employees (first_name, age) VALUES ('Matt' , 34);
-SELECT age FROM employees;
-SELECT * FROM employees;
-UPDATE employees SET weight = 300 WHERE first_name = 'Bill';
-DELETE FROM employees WHERE first_name = "Bill";
+INSERT INTO people (first_name, age) VALUES ('Matt' , 34);
+SELECT age FROM people;
+SELECT * FROM people;
+UPDATE people SET weight = 300 WHERE first_name = 'Bill';
+DELETE FROM people WHERE first_name = "Bill";
 
 -- OPERATORS
-SELECT * FROM employees WHERE age != 63;
-SELECT * FROM employees WHERE age < 63;
-SELECT * FROM employees WHERE age > 63;
-SELECT * FROM employees WHERE age >= 63;
-SELECT * FROM employees WHERE age <= 63;
-SELECT * FROM employees WHERE first_name first_name LIKE "%Charlie%";
-SELECT * FROM employees WHERE first_name NOT LIKE "%Charlie%";
-SELECT * FROM employees WHERE age IS NULL;
-SELECT * FROM employees WHERE age IS NOT NULL;
+SELECT * FROM people WHERE age != 63;
+SELECT * FROM people WHERE age < 63;
+SELECT * FROM people WHERE age > 63;
+SELECT * FROM people WHERE age >= 63;
+SELECT * FROM people WHERE age <= 63;
+SELECT * FROM people WHERE first_name first_name LIKE "%Charlie%";
+SELECT * FROM people WHERE first_name NOT LIKE "%Charlie%";
+SELECT * FROM people WHERE age IS NULL;
+SELECT * FROM people WHERE age IS NOT NULL;
 
 
 -- AND/OR
-SELECT * FROM employees WHERE first_name = 'Matt' AND age = 43;
-SELECT * FROM employees WHERE first_name = 'Matt' OR age = 49;
+SELECT * FROM people WHERE first_name = 'Matt' AND age = 43;
+SELECT * FROM people WHERE first_name = 'Matt' OR age = 49;
 
 -- ORDER
-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, first_name ASC;
+SELECT * FROM people ORDER BY age DESC;
+SELECT * FROM people ORDER BY age ASC LIMIT 2;
+SELECT * FROM people ORDER BY age ASC LIMIT 2 OFFSET 1;
+SELECT * FROM people ORDER BY age DESC, first_name ASC;
 
 -- ALTER TABLE
-ALTER TABLE employees ADD COLUMN weight FLOAT;
-ALTER TABLE employees DROP COLUMN height;
-ALTER TABLE employees ADD COLUMN height FLOAT AFTER first_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;
+ALTER TABLE people ADD COLUMN weight FLOAT;
+ALTER TABLE people DROP COLUMN height;
+ALTER TABLE people ADD COLUMN height FLOAT AFTER first_name;
+ALTER TABLE people MODIFY COLUMN height FLOAT AFTER age;
+ALTER TABLE people ADD COLUMN id INT FIRST;
+ALTER TABLE people ADD COLUMN dob DATETIME;
+ALTER TABLE people CHANGE dob date_of_birth DATETIME;
+ALTER TABLE people ADD COLUMN id INT NOT NULL AUTO_INCREMENT PRIMARY KEY FIRST;
 
 -- AGGREGATION
-SELECT COUNT(*), age FROM employees GROUP BY age;
-SELECT SUM(salary), age FROM employees GROUP BY age;
-SELECT AVG(salary) FROM employees GROUP BY age;
-SELECT MIN(salary) FROM employees GROUP BY age;
-SELECT MAX(salary) FROM employees GROUP BY age;
-SELECT GROUP_CONCAT(first_name) FROM employees GROUP BY age;
-SELECT GROUP_CONCAT(first_name), age, height FROM employees GROUP BY age, height;
+SELECT COUNT(*), age FROM people GROUP BY age;
+SELECT SUM(salary), age FROM people GROUP BY age;
+SELECT AVG(salary) FROM people GROUP BY age;
+SELECT MIN(salary) FROM people GROUP BY age;
+SELECT MAX(salary) FROM people GROUP BY age;
+SELECT GROUP_CONCAT(first_name) FROM people GROUP BY age;
+SELECT GROUP_CONCAT(first_name), age, height FROM people GROUP BY age, height;
 
 -- JOINS
-SELECT * FROM employees JOIN companies ON employees.employer_id = companies.id;
-SELECT * from employees JOIN companies;
-SELECT * FROM employees RIGHT OUTER JOIN companies ON employees.employer_id = companies.id;
-SELECT * FROM employees LEFT OUTER JOIN companies ON employees.employer_id = companies.id;
+SELECT * FROM people JOIN companies ON people.employer_id = companies.id;
+SELECT * from people JOIN companies;
+SELECT * FROM people RIGHT OUTER JOIN companies ON people.employer_id = companies.id;
+SELECT * FROM people LEFT OUTER JOIN companies ON people.employer_id = companies.id;
 ```