If function or switch function to replace value

Hi MichelleQLi ,

For simple conditional columns you can use the Add Conditional Column feature in the Query Editor. By the way, this editor uses M as the language. DAX is used once you've loaded your data into the model.

https://turbofuture.com/computers/A-Comparison-Between-M-Language-and-DAX-in-Power-BI 

Hi MichelleQLi ,

According to your description, here are my steps you can follow as a solution.

(1) This is my test data.  

(2) We can create a calculated column.

Column = IF('Table'[Column1]=="I" && 'Table'[Table3.Column6]<>BLANK(),'Table'[Table3.Column6],'Table'[Column6])

(3) Then the result is as follows.

Best Regards,

Neeko Tang

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