Yes sure Anutej.

In case object, there is a case record type called "credit limit exceeded". Every case in this record type comes in with a subject. This subject for every account and every sales order is unique. The Subject is in a format : "Credit Hold: Account name: Sales Order".

I want to allow salesforce to create duplicate cases but once a case is created with an exsiting subject line, it should flag that case.

For that I have created a field called "Is Duplicate". So when a case comes in with a subject which already exist in case object, it ticked that field.

But as in our organisation we have other case record types as well, such as accounts enquiry. In that case every case has the same subject, so now trigger is also marking those cases as duplicate. Which I dont want to do.

Now the concern is, I only want to allow this trigger to work for one record type.

But following other posts and solution above error is coming in.

Hope that helps.

Regards 

trigger DuplicateCase on Case (before insert, before update) 
{
	if(trigger.isbefore && trigger.isinsert)
	{
	List<Case> casesList = new List<Case>();
    set<string> subs= new set<string>();
    Map<String, Integer> casemap= new Map<String, Integer>();    

 	Id recordTypeId = [Select Id From RecordType Where Name = 'Credit_Limit_Exceeded'].Id;
    	for (case s : Trigger.new)
    	{
        	if(s.RecordTypeId == recordTypeId)
           	{ 
           		String Str= '%'+s.Subject+'%';
				subs.add(Str);
			}
    	}
	
	casesList=[select Id, Subject from Case Where RecordTypeId= :recordTypeId AND Subject LIKE :subs];

	for(Case c: casesList)
	{
		if(casemap.containsKey(c.Subject))
		{
		Integer temp= ((Integer)casemap.get(c.Subject))+1;
		casemap.put(c.Subject,temp);
		}
		else
		{
		casemap.put(c.Subject,1);
		}
	}

   	for(Case c:trigger.new)
   	{
   		if(casemap.get(c.Subject)>1) { c.Is_Duplicate__c = TRUE;}
   		else{c.Is_Duplicate__c = FALSE;}
   	}
	}
}