USING SUBSTRING IN CASE STATEMENT

Summary:

Trying to extract Working Hours from ORC Requisition Internal Description using SUBSTRING in a CASE statement

Content (please ensure you mask any confidential information):

Hi,

I'm trying to extract the Working Hours that are posted in an ORC Recquistion. They are contained in our Internal Description and I can get the following SUBSTRING function to work on its own, but when I try to wrap it in a CASE statement to account for instances where there are no Working Hours included, the analytic errors. The individual components of the CASE statement work but as soon as I add the SUBSTRING function it fails. Any advice would be gratefully received.