"New column" greyed out in Semantic Model builder

Hello dolphinantonym,

Because the semantic model is based on a direct lake mode, the option is grayed (disabled).

But how do you do it ? 

Option 1 :  add the calculated column directly in the source (whether is excel or create view or other sources)

Option 2 : if you are storing data into a lakehouse, you can use notebooks with sparkSQL or pyspark or Dataflow gen2 (low code) to add calculated columns into the table in your lakehouse.

Option 3 : if you are storing data into a warehouse : add the column in your warehouse, change dataflow, change column mapping and rerun.

I found this video helpful for your need : https://www.youtube.com/watch?v=kFQ-dNBUUF4

Hope it can help you ! 

Best regards,

Antoine

Thank you for the reply.

I am storing data in a Lakehouse, but none of those options apply because I want my calculated column to handle unmatched cases in reports. The below shows the kind of thing I have in my Lakehouse - Table 1 is relationshipped to Table 2, but when building a report based primarily on Table 1 I want to calculate something that can show "No details available":

I could create the report as a table using Notebooks if I wanted to, but that would result in storing an unneccessary amount of data so I'm looking into ways to calculate this dynamically in the Semantic Model instead so that it is only calculated at the point of use.