Exercise: Fn to find domain name using reverse, charindex

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 ==> Scalar functions  (6 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).

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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. This exercise refers to the following two tables from this database:

SQL exercise - Avoiding scalar functions (image 1)

Each country's domain (eg .UK) can have lots of corresponding websites

Create a function to return the domain suffix from any website URL (eg the Wise Owl website URL would return .uk).

You may find it easier to use the reverse function to reverse the order of the URL, then use the charindex function to find the first full stop.  Don't forget to check for errors - if charindex returns 0, then this isn't a valid URL!

Use your function to show all websites where the domain reported by the DomainId column isn't the same as the actual domain suffix:

SQL exercise - Avoiding scalar functions (image 2)

Your query should show 7 sanitised adult sites and one Mexican mistake!

Optionally, save the code to generate this function as Return country domain.sql, then close it down.

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