Exercise: Inserting 3 winner rows into table variable

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

Category ==> SQL  (192 exercises)
Topic ==> Temporary tables and table variables  (9 exercises)
Level ==> Average difficulty
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). Once you've done this:
  1. Go into SQL Server Management Studio;
  2. Open the SQL file you've just unzipped (you can press CTRL + O to do this); then
  3. Execute this script.

This will generate the database that you'll need to use in order to do this exercise (note that the database and script are only to be used for exercises published on this website, and may not be reused or distributed in any form without the prior written permission of Wise Owl).

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The aim of this exercise is to create a table variable, and populate it so that it holds the category, country and continent with the highest number of events for each:

The table of winners

Where we should end up - although there's a way to go yet to get there.

The easiest way to start is to first write three select statements:

Highest count from three tables

Use apostrophes to create the first column value for each row (eg 'Category'); the other two columns come from combining SELECT TOP 1 with a GROUP BY clause.

 

Now declare a TABLE variable with three columns: Source, Winner and Number of events. Insert the results of your three SELECT statements into this table, either by using UNION or by using 3 separate INSERT statements.

You should now be able to display the results of this query:

Winners of the table variable test

Some would say that the combination of these three haven't produced winners!

 

Optionally save this as Declaring winner table.sql, then close it down.

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