Hi all,

I have a requirement , Add all opportunity Amount fields , display total amount in Account object.

i have code it's working for inserting a record in opportunity.

But update and delete operation does not work.

i know through Roll-up summary we can but i want it from trigger only please help me ...........

trigger AmountTask on Opportunity (after insert,after update){
  if(Trigger.isinsert){
        Map<id,decimal> acctotal = new Map<id,decimal>();
        for(opportunity opp :trigger.new){
            if(opp.amount!=null){    
                if(acctotal.get(opp.accountid)==null){
                    acctotal.put(opp.accountid,opp.amount);
                    System.Debug('++++++opp.accountid--------Null--->'+acctotal.get(opp.accountid));
                }
                else
                {
                    decimal amt = 0;
                    amt = acctotal.get(opp.accountid)+opp.amount;
                    acctotal.put(opp.accountid,amt);
                    System.debug('++++++++++opp.accountid--------NotNull--Total Amount---->'+acctotal.get(opp.accountid));
                    
                }
            }
        }
        list<account> alist= new list<account>();
        list<account> accList = [select total_amount__c from account where id in:acctotal.keyset()];
        for(account a:acclist){
            a.total_amount__c+=acctotal.get(a.id);
            alist.add(a);
            System.debug('++++++++++opp.accountid--------finally---->'+a.total_amount__c);
        }
        update alist;
  }

}

plz help me thank you guys,