I have created whole dollar discount fields on the Opportunity Products that Roll Up in a custom amount field on the Opportunity however I have a request to override the standard Salesforce amount field with the custom roll up field I have tried to accomplish this with a workflow with a field update this is not working...any suggestions would be great!

Below is the field update I have created:

Hi if anyone can help with creation of a validation rule that ensures the first 3 digits are "INV" and the last 5 digits are numerical only it would be great.  Below is what I created so far however it doesn't ensure the last 5 are numerical.

NOT(
OR(
ISBLANK( X4D_Invoice__c),
LEN( X4D_Invoice__c) = 8,
LEFT(X4D_Invoice__c,3 ) = "INV"))

I have created whole dollar discount fields on the Opportunity Products that Roll Up in a custom amount field on the Opportunity however I have a request to override the standard Salesforce amount field with the custom roll up field I have tried to accomplish this with a workflow with a field update this is not working...any suggestions would be great!

Below is the field update I have created:

Hi if anyone can help with creation of a validation rule that ensures the first 3 digits are "INV" and the last 5 digits are numerical only it would be great.  Below is what I created so far however it doesn't ensure the last 5 are numerical.

NOT(
OR(
ISBLANK( X4D_Invoice__c),
LEN( X4D_Invoice__c) = 8,
LEFT(X4D_Invoice__c,3 ) = "INV"))