Update questions.sql

SQL Deep Dive/Distinct/questions.sql

@@ -4,23 +4,25 @@
 * Question: What unique titles do we have?
 */
 
-SELECT * FROM titles;
+SELECT DISTINCT(title)
+  FROM titles
 
 
 /*
 * DB: Employees
 * Table: employees
 * Question: How many unique birth dates are there?
 */
-
-SELECT * FROM employees;
+SELECT DISTINCT(COUNT(birth_date))
+  FROM Employees;
 
 /*
 * DB: World
 * Table: country
 * Question: Can I get a list of distinct life expectancy ages
 * Make sure there are no nulls
 */
-
-SELECT * FROM country;
-
+SELECT DISTINCT(lifeexpectancy)
+FROM country
+WHERE lifeexpectancy is not null
+order BY  lifeexpectancy ASC;

SQL Deep Dive/Order By/questions.sql

@@ -3,17 +3,27 @@
 * Table: employees
 * Question: Sort employees by first name ascending and last name descending
 */
+SELECT first_name, last_name
+FROM employees
+ORDER BY first_name ASC, last_name desc;
 
 
 /*
 * DB: Employees
 * Table: employees
 * Question: Sort employees by age
 */
+SELECT first_name, last_name, EXTRACT(YEAR FROM AGE(birth_date)) AS Age
+FROM employees
+ORDER BY age;
 
 
 /*
 * DB: Employees
 * Table: employees
 * Question: Sort employees who's name starts with a "k" by hire_date
 */
+SELECT *
+FROM employees
+WHERE first_name ILIKE 'k%'
+ORDER BY hire_date;