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Software ==>	SQL (203 exercises)
Topic ==>	Temporary tables and table variables (13 exercises)
Level ==>	Average difficulty
Subject ==>	SQL training

Add rows one by one within a loop into a temporary table that you've created

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.

Before you can do this exercise, you'll need to download and unzip this file . Once you've done this:

Go into SQL Server Management Studio;
Open the SQL file you've just unzipped (you can press CTRL + O to do this); then
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).

The aim of this exercise is to create a temporary table showing the most eventful country for each year. One way to do this is to create a temporary table, and populate its rows within a loop.

The first 4 rows out of the 95 years that your query should return.

Note that this is not the only - or even the best - way to do this, but it does provide a useful exercise on temporary tables!

For details of how to proceed, please turn the page!

First write a query to create a temporary table with 3 columns:

Column	Contents
Year of events	Each year in the database
Country of events	The country for that year having most events
Number of events	The number of events for this country in this year

Declare variables to hold the earliest and latest event years, and set their values:

Set the value of your two variables to hold the earliest and latest year referenced in the tblEvent table.

Use these variables to start a WHILE loop, which begins at the first year and stops at the last year, adding 1 each time round the loop.

Within your loop, insert one record into your temporary table containing:

The current year number (the value of your counter variable within the loop);
The country having the most events for this year; and
The number of events for this country.

You can get this information by showing the number of events for each country, then adding the TOP 1 clause to pick out just the first country, as ordered by the number of events.

When everything is working, optionally save this exercise as Counting the years away.sql, then close it down.

You can unzip this file to see the answers to this exercise, although please remember this is for your personal use only.

You can find other training resources for the subject of this exercise here:

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