add hw1 and hw2

Week1/solutions/hw1_dorzhiev_ardan/coffeshop.sh

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+echo 'Welcome to the Dave Coffeeshop!'
+
+if [ -f davecoffeeshop.db ]; then 
+ echo 'davecoffeeshop.db exists, using existing database'
+else
+ echo 'davecoffeeshop.db not exists => creating db file'
+ touch davecoffeeshop.db
+
+ echo 'success' 
+fi
+
+echo 'To log order, enter LOG
+To end session, enter EOS
+To end business day, enter EOD'
+
+while read command
+ do 
+  if [ $command = 'LOG' ]; then 
+   echo 'Enter Barista' 
+   read barista
+   echo 'Enter Drink'
+   read in_drink
+   echo "Barista name: $barista"
+   echo "Drinking: $in_drink"
+
+   case $in_drink in
+     "AME")
+          price=100
+          ;;
+     "ESP")
+          price=120
+          ;;
+     "CAP")
+          price=150
+          ;;
+     "LAT")
+          price=170
+          ;;
+     "RAF")
+          price=200
+          ;;
+         *)
+	  price=0
+          ;;
+   esac
+
+   if (( price > 0 )); then    
+    echo "$barista;$in_drink;$price" >> davecoffeeshop.db
+    echo 'Order was saved!'
+   else
+    echo Invalid drink c, ignoring
+   fi
+
+  elif [ $command = 'EOS' ]; then
+   echo 'End of Session' 
+   exit
+  elif [ $command = 'EOD' ]; then
+   echo 'End of Day!'
+
+   cat davecoffeeshop.db | sort -nk1 -t ";" | awk -F";" 'BEGIN {OFS=";" }\
+   ($1 == last || last == "") {sum += $3} ($1 != last && last != "")\
+   {print last, sum; sum = $3} {last = $1} END {print last, sum}' | sort -nrk2 -t ";" 
+
+  else 
+   echo 'WRONG COMMAND. USE ONLY LOG, EOD, EOS'
+  fi
+done

Week1/solutions/hw1_dorzhiev_ardan/davecoffeeshop.db

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+ARDAN;AME;100
+MARIE;RAF;200
+ARDAN;CAP;150
+MARIE;LAT;170

Week1/solutions/hw1_dorzhiev_ardan/Вывод терминала DaveCoffeeShop

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+(base) MacBook-Air-Ardan:~ ardandorzhiev$ sh ./coffeshop.sh
+Welcome to the Dave Coffeeshop!
+davecoffeeshop.db not exists => creating db file
+success
+To log order, enter LOG
+To end session, enter EOS
+To end business day, enter EOD
+LOG
+Enter Barista
+ARDAN
+Enter Drink
+AME
+Barista name: ARDAN
+Drinking: AME
+Order was saved!
+LOG
+Enter Barista
+MARIE
+Enter Drink
+RAF
+Barista name: MARIE
+Drinking: RAF
+Order was saved!
+LOG
+Enter Barista
+ARDAN
+Enter Drink
+CAP
+Barista name: ARDAN
+Drinking: CAP
+Order was saved!
+LOG
+Enter Barista
+NICK
+Enter Drink
+COLA
+Barista name: NICK
+Drinking: COLA
+Invalid drink c, ignoring
+LOG
+Enter Barista
+MARIE
+Enter Drink
+LAT
+Barista name: MARIE
+Drinking: LAT
+Order was saved!
+EOD
+End of Day!
+MARIE;370
+ARDAN;250
+EOS 
+End of Session
+(base) MacBook-Air-Ardan:~ ardandorzhiev$ cat davecoffeeshop.db
+ARDAN;AME;100
+MARIE;RAF;200
+ARDAN;CAP;150
+MARIE;LAT;170
+(base) MacBook-Air-Ardan:~ ardandorzhiev$ 

Week3/solutions/hw2_dorzhiev_ardan/hw2_task1.sql

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+/* Вывести все альбомы со средней длинной трека, большей 250 секунд. 
+ * Вывести название альбома и количество треков. (album_name, cnt).*/
+
+
+with album_track_length as (select a.album_id 
+								 , a.title as album_name
+						         , round(avg(t.milliseconds)/1000,0) avg_track_length_in_seconds
+						    from album a 
+						    join track t on a.album_id = t.album_id 
+						group by a.album_id 
+							   , a.title 
+						  having avg(t.milliseconds)/1000 > 250
+						order by a.album_id )
+
+select a.title as album_name
+	, count(t.track_id) cnt
+  from album a 
+  join track t on a.album_id = t.album_id 
+ where exists (select 1 from album_track_length atl where atl.album_id = a.album_id)
+ group by a.album_id
+ 		, a.title 
+ order by a.title 
+
+

Week3/solutions/hw2_dorzhiev_ardan/hw2_task10.sql

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+/* Для каждого альбома тип медиа определяется как наибольшая суммарный размер треков по жанру. 
+ * Для каждого исполнителя вывести тип медиа, соответствующий наибольшему количеству типов медиа по альбомам, где они участвуют.
+ * Вывести имя исполнителя, тип медиа, количество альбомов с данными типом, общее количество альбомов. 
+ * 
+ * (artist_name, media_type_name, media_cnt, whole_cnt)
+ * 
+ * */
+
+
+with album_agg as (select a.album_id 
+					 , t.media_type_id 
+					 , sum(t.bytes) size_tracks
+				  from album a 
+				  join track t on t.album_id = a.album_id 
+				  group by a.album_id 
+					 	 , t.media_type_id
+				  order by a.album_id 
+		        ) ,
+	album_media as (select a1.album_id
+						 , a1.media_type_id
+					  from album_agg a1
+					  join album a on a1.album_id = a.album_id 
+					  where (a1.album_id, a1.media_type_id) in (select a2.album_id, a2.media_type_id
+					  										      from album_agg a2 
+					  						   					 where a1.album_id = a2.album_id
+					  						   					   and a1.media_type_id = a2.media_type_id 
+					  						   				  order by a2.size_tracks desc 
+					  						   					 limit 1 
+					  										     )			      
+
+
+				   ) , 
+
+	artist_albums_media as (	select a.artist_id
+								 , am.media_type_id
+								 , count(distinct al.album_id) cnt_albums 
+						      from artist a 
+							  join album al on al.album_id = a.artist_id 
+							  join album_media am on al.album_id = am.album_id 
+							  group by a.artist_id
+								 	 , am.media_type_id
+						) ,
+
+	artist_cnt_media as (select ar.artist_id
+							  , m.media_type_id
+							  , count(distinct a.album_id) cnt_media_albums
+	   					   from album a
+	   					   join album_media m on a.album_id = m.album_id
+	   					   join artist ar on a.artist_id = ar.artist_id 
+	   				   group by ar.artist_id
+							  , m.media_type_id
+						) ,
+
+	artist_cnt_albums as (select ar.artist_id
+							  , count(distinct a.album_id) cnt_albums 
+	   					   from album a
+	   					   join artist ar on a.artist_id = ar.artist_id 
+	   				   group by ar.artist_id
+						) 						
+
+
+ select a."name" as artist_name
+ 	  , mt."name" as media_type_name
+ 	  , acm.cnt_media_albums as media_cnt
+ 	  , aca.cnt_albums as whole_cnt
+   from artist_albums_media am 
+   join artist_cnt_media acm on am.artist_id = acm.artist_id
+   join artist_cnt_albums aca on am.artist_id = aca.artist_id
+   join artist a on am.artist_id = a.artist_id 
+   join media_type mt on am.media_type_id = mt.media_type_id 
+  where am.cnt_albums in (select max(am1.cnt_albums) c 
+                            from artist_albums_media am1
+                           where am1.artist_id = am.artist_id) 
+
+
+

Week3/solutions/hw2_dorzhiev_ardan/hw2_task2.sql

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+/* Для каждого набора жанр, тип медиа вывести количество треков.
+ * Если для набора жанр, тип медиа треков нет, то такой набор выводить не требуется. 
+ * (genre_name, media_type_name, cnt) 
+ */
+
+  select g."name" as genre_name
+       , mt."name" as media_type_name
+       , count(t.track_id) as cnt_tracks
+    from track t
+    join media_type mt on t.media_type_id = mt.media_type_id 
+    join genre g on t.genre_id = g.genre_id 
+group by g.genre_id
+       , g."name" 
+       , mt.media_type_id 
+       , mt."name" 
+  having count(t.track_id) > 0 
+order by g."name"  

Week3/solutions/hw2_dorzhiev_ardan/hw2_task3.sql

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+/* Вывести сотрудников, которые старше своего менеджера, но были наняты позже своего менеджера. 
+ * Вывести полное имя сотрудника(Фамилия<Пробел>Имя), день рождения, дата найма, полное имя менеджера, день рождения, дата найма.
+ * (employee_full_name, employee_birth_date, employee_hire_date, manager_full_name, manager_birth_date, manager_hire_date)   
+ */
+
+ select concat(e.last_name, ' ', e.first_name) as employee_full_name
+      , e.birth_date as employee_birth_date
+      , e.hire_date  as employee_hire_date
+      , concat(m.last_name, ' ', m.first_name) as manager_full_name
+      , m.birth_date as manager_birth_date
+      , m.hire_date  as manager_hire_date
+   from employee e 
+   join employee m on e.reports_to = m.employee_id 
+  where e.birth_date < m.birth_date -- работник старше своего менеджера 
+    and e.hire_date > m.hire_date  -- работник нанят позже менеджера
+

Week3/solutions/hw2_dorzhiev_ardan/hw2_task4.sql

@@ -0,0 +1,28 @@
+/* Для всех треков жанра Rock и Metal, для каждого артиста подсчитать количество треков. 
+ * Вывести имя артиста, количество треков. (artist_name, qty)  
+ */
+
+   select ar."name" as artist_name
+   		, count(t.track_id) as qty 
+	 from track t
+	 join genre g on t.genre_id = g.genre_id 
+	 join album a on t.album_id = a.album_id 
+	 join artist ar on a.artist_id = ar.artist_id 
+    where g."name" in ('Rock', 'Metal')
+ group by ar.artist_id 
+        , ar."name" 
+ order by count(t.track_id)
+
+	/*select ar."name" 
+	    	 , g."name" 
+	    	 , t.track_id 
+	    	 , t."name" 
+	    	 , a.album_id 
+	    	 , a.title 
+		 from track t
+		 join genre g on t.genre_id = g.genre_id 
+		 join album a on t.album_id = a.album_id 
+		 join artist ar on a.artist_id = ar.artist_id 
+	    where g."name" in ('Rock', 'Metal')
+	 order by ar."name", t.track_id   
+ */      

Week3/solutions/hw2_dorzhiev_ardan/hw2_task5.sql

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+/* Для каждого сотрудника 
+ * подсчитать количество клиентов, 
+ * количество выполненных заказов, 
+ * количество уникальных адресов доставки 
+ * общее число приобретенных треков
+ * вывести полное имя сотрудника. 
+ * (employee_full_name, invoices_count, customers_count, addresses_count, tracks_count)
+ */
+
+    select concat(e.last_name, ' ', e.first_name) as employee_full_name
+       	 , count(distinct c.customer_id) as customers_count
+       	 , count(distinct i.invoice_id) as invoices_count
+       	 , count(distinct i.billing_address) as addresses_count
+       	 , count(iline.track_id) as tracks_count
+      from employee e 
+ left join customer c on e.employee_id = c.support_rep_id
+ left join invoice i on i.customer_id = c.customer_id 
+ left join invoice_line iline on i.invoice_id = iline.invoice_id 
+  group by e.employee_id
+         , concat(e.last_name, ' ', e.first_name) 
+
+         /* 
+  select *
+    from invoice i 
+   left join invoice_line iline on i.invoice_id = iline.invoice_id 
+
+    select e.employee_id 
+    	 , e.title  
+   		 , concat(e.last_name, ' ', e.first_name) as employee_full_name
+       	 , c.customer_id
+       	 , i.invoice_id
+       	 , i.billing_address 
+       	 , iline.track_id
+      from employee e 
+ left join customer c on e.employee_id = c.support_rep_id
+ left join invoice i on i.customer_id = c.customer_id 
+ left join invoice_line iline on i.invoice_id = iline.invoice_id 
+  order by e.employee_id */
+
+
+
+

Week3/solutions/hw2_dorzhiev_ardan/hw2_task6.sql

@@ -0,0 +1,51 @@
+/* Выполнить сегментацию клиентов по количеству букв "а" в его фамилии - Группа 'A' - 0 букв, 'B' - 1 буква, 'C' - 2 буквы, 'D' - 3 и более букв.
+ * Для каждой группы вывести количество уникальных типов медиа, купленных клиентами по трекам из различных жанров метала. 
+ * Вывести имя группы и количество уникальных типов медиа (segment_group, cnt)
+ * */
+
+  select case when LENGTH(c.last_name) - LENGTH(REPLACE(lower(c.last_name), 'a', '')) = 0 then 'A' 
+              when LENGTH(c.last_name) - LENGTH(REPLACE(lower(c.last_name), 'a', '')) = 1 then 'B' 
+              when LENGTH(c.last_name) - LENGTH(REPLACE(lower(c.last_name), 'a', '')) = 2 then 'C' 
+              when LENGTH(c.last_name) - LENGTH(REPLACE(lower(c.last_name), 'a', '')) = 3 then 'D' 
+           else 'E' end as segment_group 
+       , count(distinct t.media_type_id) as cnt
+    from customer c
+    join invoice i on c.customer_id = i.customer_id 
+    join invoice_line il on il.invoice_id = i.invoice_id 
+    join track t on il.track_id = t.track_id 
+    join genre g on g.genre_id = t.genre_id 
+   where lower(g."name") like '%metal%'
+group by case when LENGTH(c.last_name) - LENGTH(REPLACE(lower(c.last_name), 'a', '')) = 0 then 'A' 
+              when LENGTH(c.last_name) - LENGTH(REPLACE(lower(c.last_name), 'a', '')) = 1 then 'B' 
+              when LENGTH(c.last_name) - LENGTH(REPLACE(lower(c.last_name), 'a', '')) = 2 then 'C' 
+              when LENGTH(c.last_name) - LENGTH(REPLACE(lower(c.last_name), 'a', '')) = 3 then 'D' 
+           else 'E' end
+
+       /*     
+  select c.last_name
+       , i.invoice_id 
+       , il.invoice_line_id 
+       , il.track_id 
+       , t.media_type_id
+       , g.genre_id 
+    from customer c
+    join invoice i on c.customer_id = i.customer_id 
+    join invoice_line il on il.invoice_id = i.invoice_id 
+    join track t on il.track_id = t.track_id 
+    join genre g on g.genre_id = t.genre_id 
+   where lower(g."name") like '%metal%' 
+  order by c.last_name
+
+    select t.media_type_id
+    from customer c
+    join invoice i on c.customer_id = i.customer_id 
+    join invoice_line il on il.invoice_id = i.invoice_id 
+    join track t on il.track_id = t.track_id 
+    join genre g on g.genre_id = t.genre_id 
+   where lower(g."name") like '%metal%' 
+  group by t.media_type_id
+
+
+  */
+
+