# SSAS - tabular | Date calculations exercise | Show figures for the previous year, and two quarters ago

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 Software ==> SSAS - tabular  (30 exercises) Version ==> SSAS 2012 and later Topic ==> Date calculations  (3 exercises) Level ==> Relatively easy Subject ==> SSAS training
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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If you haven't already done so, create a new project called BaseModel, and import the following tables: tblCentre, tblCentreType, tblEnvironment, tblFamily, tblHabitat, tblProduct, tblPurchase, tblRegion and tblTown

Import the tblCalendar table if you haven't already done so, and create a relationship via the purchase date column:

Link the calendar and purchase tables together by the purchase date.

Now create two new measures:

Measure What it calculates
Same period last year The total quantity sold for the same period as the current query context, but in the previous year (use SAMEPERIODLASTYEAR).
Two quarters ago The total quantity sold for the corresponding dates two quarters ago (use DATEADD).