update

daten-abfragen/select-advanced.sql

@@ -0,0 +1,38 @@
+select firstname as fn
+from customers;
+
+select min(age) as min_age, max(age) as max_age, avg(age) as avg_age
+from customers;
+
+select concat(customers.firstname, ' ', lastname) as full_name
+from customers;
+
+select upper(concat(customers.firstname, ' ', lastname)) as full_name
+from customers;
+
+select length(customers.firstname) as fn_length
+from customers;
+
+select concat(customers.firstname, ' ', lastname) as full_name
+from customers
+where length(firstname) = 4; # performance is not perfect
+
+# [Aufgabe]: SELECT, LIMIT, ORDER BY
+# Welcher Vorname kam insgesamt (d.h. für ein beliebiges Geschlecht in einem beliebigen Jahr) am häufigsten vor?
+select * from baby_names order by count desc limit 1; # Linda
+select * from baby_names where gender = 'm' and year = 2000 order by count desc limit 1;
+
+select min(baby_names.year) from baby_names; # 1880
+
+select * from baby_names order by year limit 1; # 1880
+
+select count(distinct name) from baby_names where length(name) = 5; # 1590
+
+select count(distinct name) from baby_names where name like '_____'; # 1590
+
+select sum(count) from baby_names where year = 2000; # 3320671
+
+select distinct baby_names.name from baby_names order by baby_names.name asc limit 10, 10; # Aarna
+
+
+select categories.id, categories.title, replace(title, 'und', '&') from categories;