lab done

aggregation.sql

@@ -0,0 +1,58 @@
+use sakila;
+#1.1
+SELECT 
+    MIN(length) AS min_duration,
+    MAX(length) AS max_duration
+FROM film;
+#1.2
+SELECT 
+    CONCAT(
+        FLOOR(AVG(length) / 60), ' hours ',
+        FLOOR(MOD(AVG(length), 60)), ' minutes'
+    ) AS avg_duration
+FROM film;
+
+#2.1
+SELECT 
+  DATEDIFF(MAX(rental_date), MIN(rental_date)) AS operating_days
+FROM rental;
+#2.2
+select*,date_format(rental_date,'%M') as month,date_format(rental_date,'%W') as weekday from rental
+limit 20;
+#2.3
+select*,date_format(rental_date,'%W') as weekday ,
+case
+when date_format(rental_date,'%W')  in ("Monday","Tuesday","Wednesday","Thursday","Friday") then "workday"
+else "weekend"
+end as day_type
+from rental;
+#3
+select rental_duration from film;
+select sum(isnull(rental_duration)) from film;
+select title,ifnull(rental_duration,'Not Available') as rental_duration from film
+order by title asc;
+select concat(first_name," ",last_name) as full_name,substr(email,1,3) as email_prefix from customer
+order by last_name;
+
+#challenge 2
+#1.1
+select count(*) from film;
+#1.2
+select rating,count(title) as number_of_films from film
+group by rating;
+#1.3
+select rating,count(title) as number_of_films from film
+group by rating
+order by number_of_films desc;
+#2.1
+select rating,round(avg(length),2) as avg_duration from film
+group by rating
+order by avg_duration desc;
+#2.2
+select rating,round(avg(length),2) as avg_duration from film
+group by rating
+having avg_duration>120;
+
+#bonus
+SELECT last_name FROM actor GROUP BY last_name HAVING COUNT(*) = 1;
+