DAX help - Invoices & customers

[TonyR]

DAX newbie

Hi 

I'm trying to update our customer table to indicate if they have ever purchased from a certain dept which is in the invoice table.

Based on the tables below I'm trying to do this 

IsBookCustomer = IF invoices exist and invoices.salesdept = 'Books', Yes, No

Also it would be great to report the last invoice date as well

Customers

CustomeID, Name, IsBookCustomer, LastBookInvoiceDate

Invoices 

InvoiceDate, SalesDept,InvoiceAmount

Thanks in advance

Tony

[Datatouille]

Hi @TonyR,

You need to have a relationship (or a link if you prefer) between 'Customers' and 'Invoices' tables to do so. It implies to have a common key (or column) between these 2 tables.

Do you also have CustomerId column in your 'Invoices' Table ?

[TonyR]

Hi @Datatouille

My mistake, the tables & fields were simple examples to illustrate the issue. There are common keys linked between the tables, so there is a CustomerID in the Invoice table.

Thx for pointing that out.

[Datatouille · Accepted solution]

Ok, well in that case here is what I suggest:

First, compute the last date of books purchase (if any) with this calculated column (named LastBookInvoiceDate):

= CALCULATE ( MAX ( Invoices[InvoiceDate] ) , Invoices[Sales Dept] = "Books" )

Then, use the column calculated above to check if the customer has ever bought a book:

=IF ( Customers[LastBookInvoiceDate] , "Yes", "No" )

Obviously you need to have a 1 to Many relationship between Customers and Invoices Tables and the calculated columns are both created from the Customers Table.

Feel free to ask any questions if necessary 🙂

Regards,

Tristan Malherbe

Data & BI Consultant at AZEO

http://www.azeo.com/

[TonyR]

Thx @Datatouille 

Perfect Solution 🙂

Another education 🙂

Thx so much,

Tony