# Exercise: Use the EARLIER function to group purchases into bands

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 course listed below!

 Category ==> Power BI - Excel 2016  (23 exercises) Topic ==> More advanced DAX functions  (2 exercises) Level ==> Harder than average Course ==> PowerPivot / Excel Power BI
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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Create a new workbook, and import the following tables into your PowerPivot data model:

The tables you'll need for this exercise (as is our owly wont, we've given them friendly names).

Open the Word document in the above folder called Unit sizes, and paste it into your PowerPivot data model as a new table called Sizes.

Don't join this table to any other, though - it should stand alone.

Now create a calculated column in the Centre table (not a measure) to give the size verdict for each centre:

Categorise each centre into bands.

You can do this by using the CALCULATE function to show the value of the category from the Sizes table, applying these two filters:

• This row's NumberUnits value is greater than or equal to the Lower field value in the Sizes table; and
• This row's NumberUnits value is less than the Upper field value in the Sizes table.

You can refer to "This row" by using the EARLIER function - but this is still a difficult exercise, and should you get stuck an answer is shown overleaf.

Here's one possible answer to this exercise:

=CALCULATE (

VALUES ( Categories[Category] ),

EARLIER ( Centre[NumberUnits] ) < Categories[Upper],

EARLIER ( Centre[NumberUnits] ) >= Categories[Lower]

)

Finally, use this calculated column to summarise sales by size category:

How ironic that sales in the Massive category should be the smallest!

Save this workbook as Aaargh, then close it down.