I understand that you must be having some relationship between the lead and opportunity.
I think the criteria you put in on a workflow cannot have comparison between two fields of separate object..you can however acomplish this using triggers.
Create trigger on the lead field and compare the value of the field with the related Opportunity field you can then have a field update, send an email etc
It is not possible to compare the values of two fields belonging to two different objects which are not related in workflow formula criteria.. If they are related in your org, you may try the scenario as explained in the below post
That's great! Where do I start in creating the trigger? When I go to the "Trigger" under Set Up, it isn't allowing me to create a new trigger. Where do I go to do this? Thanks!
I understand that you must be having some relationship between the lead and opportunity.
I think the criteria you put in on a workflow cannot have comparison between two fields of separate object..you can however acomplish this using triggers.
Create trigger on the lead field and compare the value of the field with the related Opportunity field you can then have a field update, send an email etc
https://success.salesforce.com/answers?id=90630000000gu1LAAQ
@Sonam_SFDC
That's great! Where do I start in creating the trigger? When I go to the "Trigger" under Set Up, it isn't allowing me to create a new trigger. Where do I go to do this? Thanks!