Need help in creating prompts with custom SQL..

I'm trying to Pull some data from a table(DST_HISTORY) which isn't available in the universe so I'm using a custom SQL.

when I try to create a prompt like below it throws a missing expression error,

WHERE  DST_HISTORY.UPDATEDON  IN  @prompt('Enter values for Updatedon:','D','Dst History\Updatedon',Multi,Free,Persistent,,User:0)

I believe that 'Dst History\Updatedon' is not being recognized since that table doesn't exist in the universe.

Could someone pls advice on this.. Is there anything I'm doing wrong?

Thanks in advance,

Vignesh