Week 9

Question 1

What SQL command allows us to tally the number of non-null values of an attribute? What is the syntax?

Answer 1

COUNT()

Question 2

What SQL command allows us to determine the lowest and highest values of an attribute? What is the syntax?

Answer 2

MIN()
or
MAX()

Question 3

What SQL command allows us to compute the sum for any specified attribute? What is the syntax?

Answer 3

SUM()

Question 4

What SQL command allows us to determine the average value of an attribute? What is the syntax?

Answer 4

AVG()

Question 5

What is the function of the GROUP BY command? What is its syntax?

Answer 5

Allows us to group rows together for data collection rather than using a whole table.

SELECT ... 
FROM ...
WHERE ...
GROUP BY ...
HAVING ...
ORDER BY ...