SQL for Data-science Coursera Assignment Answers

Week 2 Quiz

1.Filtering data is used to do which of the following? (select all that apply).

Answers:

Narrows down the results of the data.

Reduces the strain on the client application

Reduce the time it takes to run the query

Removes unwanted data in a calculation

Helps you understand the contents of your data

2.You are doing an analysis on musicians that start with the letter “K”. Select the correct query that would retrieve only the artists whose name starts with this letter.

Answers:

SELECT name FROM Artists WHERE name LIKE ‘K%’;

3.A null and a zero value effectively mean the same thing. True or false?

Answers:

False

4.Select all that are true regarding wildcards

Answers:

Wildcards take longer to run compared to a logical operator

Wildcards at the end of search patterns take longer to run

5. Select the statements below that ARE NOT true of the ORDER BY clause (select all that apply).

Answers:

Cannot sort by a column not retrieved

Can be anywhere in the select statement

6. Select all of the valid math operators in SQL (select all that apply).

Answers:

+ (addition)

- (subtraction)

/ (division)

* (multiplication)

7. Which of the following is an aggregate function? (select all that apply).

Answers:

MAX()

MIN()

Count()

8. Which of the following is true of GROUP BY clauses?

Answers:

GROUP BY clauses can contain multiple columns

NULLs will be grouped together if your Group By column contains NULLs

Every column in your select statement must be present in a group by clause, except for aggregated calculations.

9. Select the true statement below.

Answers:

HAVING filters after the data is grouped.

10. Which is the correct order of occurrence in a SQL statement?

Answers:

select, from, where, group by, having