topic Re: Calculating values based on two tables in DAX Commands and Tips

Calculating values based on two tables

smartpug — Thu, 23 Mar 2023 21:54:36 GMT

Hi all,

I am a super beginner and have the following case:

Problem:

We have two tables: Products and Orders. They have a One-To-Many relationship so one Product might be in a few orders - a classic case. Product has a 'Price' column and an important note is that it's not a mandatory field - some products have the price and some products have it blank. I want to calculate a total value for each product based on the row count of related rows from the 'Orders' table. Formula like TotalValue = Product.Price * CountRows(Orders) where Orders.Product = Product

Example:
Products:

Product	Price
Pencil	2.00
Crayon	null
Backpack	10,00

If in Orders we have two Pencils - we will get a total of 4.00, if we have 5 Backpacks - we get a total of 50, and Crayon is skipped.

These values will be displayed to the user as figures for each product having a price and also as a sum of all totals.

I bet it's super easy but I'm also an absolute beginner in Power BI and DAX so I would be really thankful for any help!

Re: Calculating values based on two tables

wdx223_Daniel — Fri, 24 Mar 2023 02:38:10 GMT

if you are adding calculated column in Products table, try this code

NewColumn=COUNTROWS(RELATEDTABLE(Orders))*Products[Price]

Re: Calculating values based on two tables

smartpug — Fri, 24 Mar 2023 06:23:25 GMT

Hi,
Thanks for answering. Tried this and unfortunately, I get this error:
"A single value for column 'Price' in table 'Products' cannot be determined. This can happen when a measure formula refers to a column that contains many values without specifying an aggregation such as min, max, count, or sum to get a single result."

The problem is - when I was using aggregation for the 'Price' - e.g. Max('Price') - it was getting the highest 'Price' from the table and just multiplied it by all rows.

Re: Calculating values based on two tables

wdx223_Daniel — Fri, 24 Mar 2023 06:37:06 GMT

maybe you want a measure, instead of calculated column

NewMeasure=SUMX(Products,COUNTROWS(RELATEDTABLE(orders))*Products[Price])

Re: Calculating values based on two tables

smartpug — Fri, 24 Mar 2023 07:49:03 GMT

Yes, this is exactly what I need, thanks! Is it possible to modify this DAX to filter RELATEDTABLE(orders) to include only orders.DeliveryType = "Pickup"?

Re: Calculating values based on two tables

wdx223_Daniel — Fri, 24 Mar 2023 07:53:50 GMT

NewMeasure=SUMX(Products,COUNTROWS(FILTER(RELATEDTABLE(orders),orders[DeliveryType]="Pickup"))*Products[Price])