Age Range With NULLs

Return contacts aged between 20 and 40 inclusive. Contacts with unknown age must not appear. Order by id.

Table schema

Contacts(id INT PRIMARY KEY, name VARCHAR(20), phone VARCHAR(12), age INT, city VARCHAR(10))

Sample data

id | name | phone | age | city
1 | Anita Rao | 98200-11111 | 25 | Pune
2 | Arun Das | 98100-22222 | 31 | Delhi
3 | Bela Shah | 70000-33333 | 45 | Pune
4 | Chirag Rao | 98200-44444 | NULL | Mumbai
5 | Anil Roy | 99999-55555 | 19 | NULL