Exercise: Using COUNTROWS and RELATEDTABLE in calculated columns

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

Category ==> SSAS - tabular  (29 exercises)
Topic ==> Calculated columns  (4 exercises)
Level ==> Average difficulty
Course ==> SSAS - Tabular Model
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).

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If you haven't already done so, run the SQL script in the above folder in SQL Server Management Studio to generate a database (not for commercial use or copying) called MAM.

Create a new project and model, importing the tables tblCentreType, tblCentre and tblStore.  Create a calculated column in the centre type table to show how many rows there are in the centre table for each type:

Number of stores

The calculated column gives the same answer for every row.

The reason the answer is the same for every centre type is that no account is being taken of the relationship between the tables.  To solve this, use the RELATEDTABLE function to get:

Correct total number stores

The RELATEDTABLE function returns the centres for each centre type which match up by centre type id.

Create another calculated column giving the number of stores for each centre type:

Number of stores

The number of stores for each centre type.

 

That's it!

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