SQL | Temporary tables and table variables exercise | Joining a table variable to the events table

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Software ==> SQL  (198 exercises)
Version ==> Any version of SQL Server
Topic ==> Temporary tables and table variables  (9 exercises)
Level ==> Average difficulty
Courses ==> Fast-track SQL  /  Advanced SQL
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The aim of this exercise is to create a table variable to store a list of "odd" countries, then join this to the events table to see events that occurred in those odd countries.

For the purposes of this exercise, an "odd" country is one whose country id is an odd number!

Start by selecting the odd countries.

Select statement returning values using modulus

The easiest way to find the odd countries is to use the modulus operator on the CountryID. In the WHERE clause divide it by 2, but using % instead of /.  If the result isn't 0, then it must be odd!

 

This returns 22 countries.  Create a table variable called @OddCountries to hold 2 columns - OddName and OddNumber - and insert these countries into this table in your SQL:

Odd names and odd numbers

Here the results have been re-ordered as it felt odd-ly satisfying. Not punny?

 

Join this table to the tblEvent table. Add two criteria to the WHERE clause:

Criteria Details
Remove self-references Don't show events whose names contain the country they occurred in.
Co-terminosity Only show events where the event name and the OddName end in the same letter.

You should see 14 results, some of which are shown below:

RIGHT used in where to filter table variable

Use the RIGHT function to match the last letters.

Optionally save this as Odd requests.sql, then close it down.

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