W10

Question 1

AVG()

Answer 1

Returns a column’s average value

Question 1

SUM()

Answer 1

Returns the sum of a column’s values

Question 2

MAX()

Answer 2

Returns a column’s highest value

Question 3

MIN()

Answer 3

Returns a column’s lowest value

Question 4

COUNT()

Answer 4

Returns the number of rows in a column

Question 5

Summary Queries

Answer 5

Summary queries are queries that contain one or more aggregate functions.

Question 6

Aggregate Functions

Answer 6

operate on a set of rows to calculate and return a single value.

Question 7

GROUP BY

Answer 7

The GROUP BY clause is used when you have an aggregate function that you want to use on the grouped data.

Question 8

HAVING

Answer 8

This clause also works with aggregate functions and allows you to filter the groups. It works a lot like the WHERE clause but the WHERE clause filters rows and the HAVING clause filters groups.

Question 9

ROLLUP

Answer 9

This operator can be used with grouping and aggregates allowing you to add one or more summary rows to your results.

Question 10

SELECT clause order

Answer 10

SELECT
FROM
WHERE
GROUP BY
HAVING
ORDER BY
LIMIT

Question 11

SELECT order of execution

Answer 11

FROM
WHERE
GROUP BY
HAVING
SELECT
ORDER BY
LIMIT