Column Expression Node: Comparing values across multiple rows

Hi everyone,

I’m struggling to get the following code for the column expression node right:

if ( column(“A”) - column(“A”, -1) && column(“B”) <> column(“B”, -1) // change in values between rows ) {column(“C”)} else {toNull(“”)}

Could anyone point out my mistakes?

Multi-row access is activated:

Thanks and best,

Eren