Sample Count, Group By, and Aggregate Question
Sample question only. The task is similar to what will be evaluated during the exam.
Task
Imagine you have a table such as email_clicks below with the following fields.
| field | type |
| email_click_id | int |
| customer_id | int |
| email_id | int |
| email_click_date | date |
| email_subject | varchar |
Create a view that gets a list of all of the customer IDs that had multiple email_clicks. The output should be two columns – 1 for the customer_id and another for the number of email clicks.
Expected Output
| customer_id | number_of_clicks |
| 100 | 2 |
Sample Join Question
Sample question only. The task is similar to what will be evaluated during the exam.
Task
Imagine you have tables such as email_clicks and customers below
email_clicks
| field | type |
| email_click_id | int |
| customer_id | int |
| email_id | int |
| email_click_date | date |
| email_subject | varchar |
customers
| field | type |
| customer_id | int |
| customer_name | varchar |
| customer_joined_date | date |
Create a view that gets a list of all of the customer names that have clicked on at least one email.
Expected Output
| customer_name |
| Jane |
| Alex |
Finding Nulls Question
Sample question only. The task is similar to what will be evaluated during the exam.
Task
Imagine you have a table such as email_clicks below.
| field | type |
| email_click_id | int |
| customer_id | int |
| email_id | int |
| email_click_date | date |
| email_subject | varchar |
Create a view that gets a list of all of the customer_ids and email_ids that are missing an email_subject (i.e. the email_subject is NULL).
Expected Output
| customer_id | email_id |
| 101 | 2000 |
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