Amir G - All wrapped up here :D

Class_Select.sql

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+USE publications; -- schema
+SELECT  * -- 1. COLUMNS
+	FROM authors;  -- 2. TABLE
+
+SELECT au_id, phone, city -- 1. Columns
+	FROM authors; -- 2. table
+
+SELECT au_id AS ID, phone, city
+	FROM authors; -- It changes in the "print"
+				  -- Result set
+
+
+SELECT au_id AS ID, phone AS telefono, city
+	FROM authors;    
+
+-- Choosing what columns
+-- Choose columns based on the rows: filter
+​
+SELECT au_lname, au_fname, city
+FROM authors
+	WHERE city = "Oakland";
+
+-- WHERE: filter. Marjorie
+SELECT au_lname, au_fname, city
+FROM authors
+	WHERE city = "Oakland" 
+	AND au_fname = "Marjorie";
+
+-- Oakland or SF
+SELECT au_lname, au_fname, city
+	FROM authors
+	WHERE city = "Oakland" OR city = "San Francisco";
+
+SELECT *  
+FROM authors
+	WHERE city = "Oakland" OR city = "San Francisco";
+​
+-- You can filter by something
+-- even if you're not selecting that something
+SELECT au_lname, au_fname
+	FROM authors
+	WHERE city = "Oakland" OR city = "San Francisco";
+​
+-- Q: All columns but one
+SELECT au_lname, au_fname, phone, address, city, state,
+zip, contract
+	FROM authors;
+
+-- Multiple conditions
+-- business AND price > 20
+-- OR pyschology
+​
+-- titles
+-- "Expensive-ish business " or psychology (no matter the price)
+SELECT * 
+	FROM titles
+    WHERE (price > 10
+		AND type = "business")
+    OR type = "psychology";
+-- without parenthesis
+SELECT * 
+	FROM titles
+    WHERE price > 10
+		AND type = "business"
+    OR type = "psychology";
+​
+-- Business AND psych IF price for either is > 10
+SELECT * 
+	FROM titles
+    WHERE price > 10
+		AND (type = "business"
+    OR type = "psychology");
+​
+-- employees
+-- 1. Import employees
+-- 2. New: employees
+USE employees;
+SELECT * from salaries;
+​
+SELECT * FROM employees;
+-- All the women
+SELECT * 
+	FROM employees 
+	WHERE gender = "F";
+
+-- W,Nevin
+​
+SELECT * 
+	FROM employees 
+	WHERE gender = "F"
+    AND FIRST_NAME = "Nevin";
+​
+-- Uppercase when filtering
+-- SQL: NOT case-sensitive for syntaz and filterng
+-- MySQL
+​
+SElECT * 
+	from employees 
+	wHErE geNdeR = "f"
+    AND FIRST_NAME = "NEVIN";
+
+SELECT * FROM employees; -- readability
+​
+-- Men named Bezalel
+-- Or just women
+SELECT * FROM employees
+	WHERE 
+		(first_name = "Bezalel"
+		AND gender = "M")
+	OR gender = "F";
+​
+-- Q: MEN named Bezalel or Women born after 1989
+SELECT * FROM employees
+	WHERE 
+		(first_name = "Bezalel"
+		AND gender = "M")
+	OR gender = "F";
+
+-- Men: "Hugo", "Ramzi", "Mark"
+SELECT * 
+FROM employees
+WHERE gender = "M"
+AND FIRST_NAME 
+	IN ("Hugo", "Ramzi", "Mark");
+
+-- Excluding names
+SELECT * 
+FROM employees
+WHERE gender = "M"
+AND FIRST_NAME 
+	NOT IN ("Hugo", "Ramzi", "Mark");
+​
+-- Similiar "Patricia" "Patricio"
+SELECT * 
+	FROM employees
+    WHERE first_name 
+    LIKE ("Patrici_"); -- _ one of anything
+
+-- Regex: REGEXP 
+select * from employees
+where gender = "F";
+-- where first_name = "Anneke";
+​
+​
+-- Names that start with Ann
+	-- Anneke, Annemarie, Anneli, etc
+
+SELECT * FROM employees
+Where gender = "f" 
+and first_name LIKE ("ann%"); -- % regex: .*
+​
+-- Q: what if I want to literally look for 
+-- an underscore: you need to escape the character
+-- we do that using:[_] (Uri)
+​
+select * from employees;
+​
+-- Everyone born in the 60s
+SELECT * FROM employees
+	WHERE birth_date LIKE ("196%"); -- 1964-06-02
+​
+-- Q: can we put between?
+SELECT * FROM employees
+	WHERE birth_date 
+		BETWEEN "1960-01-01" AND "1989-12-31"; -- including (confirmed)
+​
+-- input the years "1990", between works with date type
+-- it also works with something else
+​
+SELECT * FROM employees
+WHERE first_name BETWEEN "A" AND "C"; -- between 
+​
+-- A-C: A and b (C is not included)
+​
+-- All the women hired in the 90s
+SELECT * 
+	FROM employees
+    WHERE hire_date LIKE ("199%")
+    AND gender = "F";
+​
+-- $145,732
+​
+SELECT * FROM salaries
+	where salary >= 70000;
+
+-- 70-80 range
+​
+SELECT * FROM salaries
+	WHERE salary BETWEEN 70000 AND 80000; -- Included
+
+SELECT * FROM salaries
+	WHERE salary BETWEEN 70000 AND 80000
+ORDER BY salary;
+​
+SELECT * FROM salaries
+	WHERE salary BETWEEN  70000 AND 80000
+ORDER BY salary ASC; -- default
+​
+SELECT * FROM salaries
+	WHERE salary BETWEEN 70000 AND 80000
+ORDER BY salary DESC;
+​
+-- Average salary for this database :( 
+SELECT AVG(salary) 
+	FROM salaries;
+    -- $63,810.74
+
+-- Total amount of salaries pasid by the company
+SELECT SUM(salary) 
+	FROM salaries;
+	-- 181480757419
+
+-- How many employees?
+SELECT COUNT(*) FROM employees; -- 300027
+SELECT COUNT(first_name) FROM employees; -- 300027
+​
+SELECT COUNT(*) from salaries; -- 2844047
+​
+SELECT * FROM salaries
+	WHERE salary IS NOT NULL;
+​
+SELECT * FROM employees
+	WHERE first_name IS  NULL; -- db is ok
+
+-- Salaries
+-- IRPF (taxes), 15%
+-- after_tax
+-- gross, after_tax = salary * 0.85
+select * from salaries;
+​
+SELECT salary AS gross, 
+	(salary * 0.85) AS worker_gets,
+    (salary * 1.5) AS company_spends
+FROM salaries
+ORDER BY company_spends DESC; -- asc is the default
+​
+-- Table salaries
+-- Table employees
+​
+SELECT salary AS gross, 
+	(salary * 0.85) AS worker_gets,
+    (salary * 1.5) AS company_spends
+FROM salaries
+ORDER BY company_spends DESC;
+​
+​
+SELECT first_name, salary, gender 
+	FROM salaries
+		JOIN employees
+			ON	employees.emp_no = salaries.emp_no; 
+-- Joining tables
+SELECT AVG(salary) as mean_salary, gender 
+	FROM salaries
+		JOIN employees
+			ON	employees.emp_no = salaries.emp_no
+	GROUP BY gender;