Hi, In NetSuite, without using SuiteScript, I want to add a validation on the Sales Order form and prevent that Sales Order from being created if the "PO/Check #" fields on the Sales Order is same/exact match with any other existing Sales Order record. Is this possible to do in NetSuite by any means other than SuiteScript (probably with workflow)? If Yes, what will be the required steps?

This is not possible via workflow but if you don't mind using a script we have a free tool that does exactly what you need https://www.mavencloud.tech/mavencloudtools