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Q1

Which of the following is a valid aggregate function in SQL? Check only those that apply.

Question 1 options:

	AVG
	LEAST
	COUNT
	MIN
	MOST
	SUM

Q2

Which of the following aggregate functions will only operate on a numeric value expression? Check only those that apply:

Question 2 options:

	MIN
	MAX
	AVG
	COUNT
	SUM

Q3

When applying DISTINCT to the value being calculated in an aggregate function like COUNT, what is the effect?

SELECT COUNT(DISTINCT StreetName) FROM ADDRESSES;

Question 3 options:

	To count only unique values
	To make a distinction between rows and columns
	To add a summary COUNT for all groupings
	To include duplicate values

Q4

A query is limited to a single aggregate calculation in its SELECT clause.

Question 4 options:

	True
	False

Q5

The GROUP BY clause groups the rows of a result set based on one or more columns or expressions. In the example below, what will the value from COUNT(*) represent?

SELECT Department, COUNT(*) FROM EMPLOYEES GROUP BY Department;

Question 5 options:

	The total number of departments
	The total number departments for each employee
	The total number of employees
	The total number of employees in each department

Q6

Specify the correct order in which each of the six SQL clauses must be placed:

Question 6 options:

123456	GROUP BY
123456	WHERE
123456	ORDER BY
123456	SELECT
123456	FROM
123456	HAVING

Q7

The GROUP BY clause can contain more than one value (separated by commas). In the query below, what does SUM(Salary) represent?

SELECT Department, State, SUM(Salary) FROM EMPLOYEES GROUP BY Department, State;

Question 7 options:

	The total salary budget for the organization
	The salary budget for each state
	The salary budget for each department
	The salary budget for each combination of department and state

Q8

The WHERE clause and the HAVING clause can both limit rows in the result set based on logical conditions. What is the difference between the two clauses?

Question 8 options:

	HAVING cannot use the logical OR operator
	WHERE is limited to a single condition
	WHERE requires a corresponding GROUP BY
	HAVING can make comparisons against aggregate functions

Q9

Conditions comparing against non-aggregate values must be placed in the WHERE clause (never in the HAVING clause).

Question 9 options:

	True
	False

Q10

What is the ROLLUP operator used for in the GROUP BY clause?

Question 10 options:

	To save memory in query execution
	To add a summary total for each grouping
	To group by all values - even if they do not match WHERE clause conditions
	To group based on unique values

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