feat: added 3 sql queries to my sql file

Author: calvin

lesson_25/db/db_app/src/main/resources/queries/calvinrobinson.sql

@@ -0,0 +1,8 @@
+-- Query 1: Counts of media items by type
+SELECT type, COUNT(*) as count FROM media_items GROUP BY type;
+
+-- Query 2: Sum of total pages checked out by guests
+SELECT SUM(mi.pages) as total_pages_checked_out FROM checked_out_items coi JOIN media_items mi ON coi.item_id = mi.id;
+
+-- Query 3: All guests and their corresponding checked out items
+SELECT g.name, g.email, coi.item_id, coi.due_date FROM guests g LEFT JOIN checked_out_items coi ON g.email = coi.email;