Answers and explanations · Filter rows without losing the unknowns

Exercise 03a

Order 1007 is pending and falls inside February. Cancelled orders elsewhere in the quarter are outside this question.

SELECT order_id,status FROM aabha_sql.orders WHERE status<>'completed'
 AND order_date>=DATE '2025-02-01' AND order_date<DATE '2025-03-01' ORDER BY order_id;

Expected output:

Runnable answer: sql/solutions/03a.sql

Exercise 03b

Customers 1, 4 and 8 are in Pune; customer 6 has an unknown city. IS NULL includes the unknown case deliberately.

SELECT customer_id,customer_name FROM aabha_sql.customers
WHERE city='Pune' OR city IS NULL ORDER BY customer_id;

Expected output:

Runnable answer: sql/solutions/03b.sql