Need to set the Number field Unique and delete all duplicate records

[SNOW46]

Hi All,

I want to set the Number field for Incident as Unique, But when I am trying to set it as Unique, its showing an error as "New Unique index skipped: Requested columns (number) on table (task) contain duplicate values. You must remove duplicate values and then try again." 

Can anyone let me know how to fix this issue. I want to delete all duplicate Incident Records but I am not finding any possibilities or tricks to fix this.

Thanks,

SNOW@Das 

[rad2]

You can run a background script and delete the duplicates -

https://community.servicenow.com/community?id=community_question&sys_id=fa709ee3dbec9fc87b337a9e0f961991

var gr = new GlideRecord('u_incident');
gr.groupBy('number');
gr.query();
while(gr.next()){
  var inc = new GlideRecord('u_incident');
  inc.addQuery('number', gr.number);
  inc.query();
  inc.next();
  while(inc.next()){
   inc.deleteRecord();
  }
}