Microsoft Access
Advanced queries exercise
Harder than average exercise
This Microsoft Access ADVANCED QUERIES exercise is provided to allow potential course delegates to assess their suitability for the Wise Owl ACCESS INTRODUCTION FOR DEVELOPERS course only, and may not be reproduced in whole or in part in any format without the prior written consent of Wise Owl.
Exercise: Expressions - error in population density
A full answer to this exercise is provided as part of the training course!
| 1) | Download the files needed to start this exercise: exercise-715.zip (and click here if you experience any problems unzipping this file after downloading it). |
| 2) | Open the database in the above folder. |
| 3) | Create a new field called Density which calculates the population density of each country (in a moment we will compare this with the one which is already in the table): |
The start of your query should look like this
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| 4) | Save this query as PopulationDensity, then close it down. |
| 5) | Create another query based on the first one which includes a new field showing the error between the PeoplePerSquareMile field report and the Density field that you have calculated: |
Use the ABS function to find the absolute value of the error as a positive amount
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| 6) | Sorting as above should revealt that the biggest error reported is for Libya, but that most countries' population densities are correctly calculated. |
| 7) | Save your query as PopulationDensityErrors, then close it and the database down. |
Thank you for showing an interest in this Access Introduction for Developers training course! As mentioned above, full answers to this and other exercises are provided on the course. On all Wise Owl scheduled courses delegates can take away these model answers (together with their own efforts!) on a free USB stick.
