[ADD] HAVING and DISTINCT functions

Author: stivenramireza

classes/06-having-function.sql

@@ -0,0 +1,15 @@
+SELECT
+	country,
+	COUNT(*)
+FROM users
+GROUP BY country
+HAVING COUNT(*) > 5
+ORDER BY COUNT(*) DESC;
+
+SELECT
+	country,
+	COUNT(*)
+FROM users
+GROUP BY country
+HAVING COUNT(*) BETWEEN 1 AND 5
+ORDER BY COUNT(*) DESC;

classes/07-distinct-function.sql

@@ -0,0 +1,2 @@
+SELECT DISTINCT(country)
+FROM users;