Exercise: Compare usage proportions for 2 countries

This exercise is provided to allow potential course delegates to choose the correct Wise Owl Microsoft training course, and may not be reproduced in whole or in part in any format without the prior written consent of Wise Owl.

The answer to the exercise will be included and explained if you attend the Wise Owl course listed below!

Category ==> SQL  (115 exercises)
Topic ==> Derived tables and CTEs  (7 exercises)
Level ==> Harder than average
Course ==> Advanced SQL
Before you can do this exercise, you'll need to download and unzip this file (if you have any problems doing this, click here for help).

You need a minimum screen resolution of about 700 pixels width to see our exercises. This is because they contain diagrams and tables which would not be viewable easily on a mobile phone or small laptop. Please use a larger tablet, notebook or desktop computer, or change your screen resolution settings.

If you haven't already done so, run the stored procedure in the above folder to generate a database of the world's leading websites. The tables we will use are:

SQL exercise - Derived tables and CTEs (image 1)

The tables of interest for this exercise

Create a stored procedure which takes in as input the names of 2 countries:

SQL exercise - Derived tables and CTEs (image 2)

Here's how we might test our stored procedure

Within this stored procedure, create a CTE giving for each website the usage proportion for that website for each of the two countries specified:

SQL exercise - Derived tables and CTEs (image 3)

For Facebook, for example, 5.1% of users are French, but only 0.9% Greek

Create a SELECT statement based on this CTE to show the results with a total:

SQL exercise - Derived tables and CTEs (image 4)

We now learn that taken together French and Greek users comprise 6% of Facebook users, for example

Optionally, save your work as Country proportions.sql, then close it down.

This page has 0 threads Add post