Quiz: Preparing data for analysis in SQL – The Data Analyst Toolkit

This quiz will test your understanding about Preparing data for analysis in SQL. Please answer the following 5 questions.

Quiz Summary

0 of 5 Questions completed

Questions:

You have already completed the quiz before. Hence you can not start it again.

Quiz is loading…

You must sign in or sign up to start the quiz.

You must first complete the following:

Results

Quiz complete. Results are being recorded.

Results

0 of 5 Questions answered correctly

You have reached 0 of 0 point(s), (0)

Current
Review
Answered
Correct
Incorrect

Question 1 of 5

1. Question
Which is true about the ROW_NUMBER function? (select all that apply)
- row_number() numbers the output of a result set, starting at 1 for the first row of the result set.
- ROW_NUMBER() is a nondeterministic function. It returns a different result every time it is run
- row_number() returns the row number of a dataset
- row_number() returns a row number for each row within a window partition, defined by the PARTITION BY clause
Correct

Incorrect
Question 2 of 5

2. Question
Which of the following is false concerning the Common Table Expressions? (select all that apply)
- Common table expression are physically created in the database.
- a CTE is a virtual table created in memory at the time of execution and whose result is used in subsequent queries.
- CTEs are defined by using the CTE statement
- CTEs improve readability and ease in maintenance of more complex queries
Correct

Incorrect
Question 3 of 5

3. Question
What are some examples of transformations possible with a CASE statement? (select all that apply)
- split data into multiple categories based on other numerical values
- aggregate and count rows that fulfill a certain condition.
- Unpivot columns
- convert data types
Correct

Incorrect
Question 4 of 5

4. Question
Which of the following is true concerning the CASE statement in SQL? (select all that apply)
- a CASE statement must include the following components: WHEN, THEN, and EN
- The CASE statement always goes in the SELECT clause, never in the WHERE clause
- ELSE is an optional component in the CASE statement
Correct

Incorrect
Question 5 of 5

5. Question
In which cases would you use the ISNULL function? (select all that apply)
- when I want to detect how many null values are in a specific column
- when I want to exclude the null values in a SELECT statement
- when I want to convert a null value to an actual value
- when I want to replace nulls by the value indicated in the second argument of the function ISNULL
Correct

Incorrect

The Data Analyst Toolkit

Quiz Summary

Information

Results

Results

Categories

1. Question

2. Question

3. Question

4. Question

5. Question