Exam DISC-DA Practice Question 19
Study guide: Exam DISC-DA
An analyst defines a SQL function age_band(age) that returns '16-24' for ages 16 to 24, '25-64' for 25 to 64 and '65+' for 65 and over, using a CASE expression with no ELSE. A driver table holds ages 15, 17, 30, 64, 70 and one NULL. The analyst runs
SELECT age_band(age) AS band, COUNT(*)
FROM driver
GROUP BY age_band(age);
How many drivers are in the group whose band is NULL?
- A) 0
- B) 1
- C) 2
- D) 3
Answer this question and see the worked solution