CLM: SQL Filter prompts and Value List Values

Hello experts,

I'm not very familiar with SQL that's why I need your help. I want to change a filter prompt (type string) in order to get a drop down selection. I think that value list values (or object reference) will be perfect for it. I used the table FCI_CONGEN_CONTRACT in order to get the "Contract Document Phase". In this case I modified the filter prompt:

Unfortunately, I will get an error message by executing the search after selecting any value (see screenshot below).

Any ideas what can be done to make this search executable?

Thanks in advance,
Heiko