I'm trying to return NULL in a CASE formula in SA Workbook. If I include NULL for a FLOAT output I get the attached error. This is an example of my formula. It doesn't matter what I am trying to do here, I'm trying to debug this error for a colleague using a similar formula. The formula works if I change NULL to 0. I thought I could use NULL in a FLOAT output type. CASE WHEN TO_NUMBER({transactionlines.item^item.cost}) = 0 THEN NULL ELSE TO_NUMBER({transactionlines.item^item.cost}) END Any ideas why I am getting this error?