Update questions.sql

SQL Deep Dive/Date Filtering/questions.sql

@@ -3,38 +3,60 @@
 * Table: employees
 * Question: Get me all the employees above 60, use the appropriate date functions
 */
-
-SELECT * FROM employees;
+SELECT *
+FROM employees
+WHERE EXTRACT(YEAR FROM AGE(birth_date)) > 60;
 
 /*
 * DB: Employees
 * Table: employees
 * Question: How many employees where hired in February?
 */
-
-SELECT * FROM employees;
+SELECT count( * ) AS Feb_Employees
+FROM employees
+WHERE EXTRACT(MONTH FROM hire_date) = 2;
 
 /*
 * DB: Employees
 * Table: employees
 * Question: How many employees were born in november?
 */
-
-SELECT * FROM employees;
+SELECT count( * ) AS Birth_Month
+FROM employees
+WHERE EXTRACT(MONTH FROM birth_date) = 11;
 
 /*
 * DB: Employees
 * Table: employees
 * Question: Who is the oldest employee? (Use the analytical function MAX)
 */
+SELECT *
+FROM employees
+WHERE AGE(birth_date) = (
+    SELECT MAX(AGE(birth_date))
+    FROM employees
+)
+LIMIT 1;
+
+The oldest employee is = jouni pocchiola
+
 
-SELECT * FROM employees;
 
 /*
 * DB: Store
 * Table: orders
 * Question: How many orders were made in January 2004?
 */
+SELECT count(*)
+FROM orders
+WHERE orderdate BETWEEN '2004-01-01' AND '2004-01-31';
+1000 orders were made in january
+
+The way to do it with the date functions is 
 
-SELECT * FROM orders;
+SELECT COUNT(*) AS Order_Count
+FROM Orders
+WHERE EXTRACT(Month FROM orderdate) = 1
+AND EXTRACT(YEAR FROM orderdate) = 2004;
 
+and the result is still 1000 orders