Salesforce Apex Trigger – Count Number of Open Tasks and Closed Tasks on the Account.

Hello guys,

Today, I’m sharing the trigger code that how you can count the number of open tasks and closed task on the account. For this, you need to make to custom fields on Account. They are –

1. Open Task field.
2. Closed Task field.

Apex Trigger code –

trigger countOpenAndClosedTask on Task (after insert, after undelete, after delete, after update) {    
    Set<Id> setOpenTaskAccountIds = new Set<Id>();
    Set<Id> setClosedTaskAccountIds = new Set<Id>();
    List<Account> listAccountUpdate = new List<Account>();
    List<Account> listOpenTaskAccounts = new List<Account>();
    List<Account> listClosedTaskAccounts = new List<Account>();
    if(Trigger.IsAfter){
        if(Trigger.IsInsert || Trigger.IsUndelete  || Trigger.isUpdate) {
            for(Task t: Trigger.new) {
                if(String.valueOf(t.WhatId).startsWithIgnoreCase('001')) {
                    if(t.Status.equalsIgnoreCase('Completed')){
                        setClosedTaskAccountIds.add(t.WhatId);
                        System.debug('@@@@Inside Completed@@@'+setClosedTaskAccountIds);
                    }
                    else {
                        setOpenTaskAccountIds.add(t.WhatId);
                        System.debug('@@@@Inside Open@@@'+setOpenTaskAccountIds);
                    }
                    if(Trigger.IsUpdate){
                        if(Trigger.oldMap.get(t.Id).WhatId != t.WhatId){
                            if(t.Status.equalsIgnoreCase('Completed')){
                                setClosedTaskAccountIds.add(Trigger.oldMap.get(t.Id).WhatId );
                                System.debug('@@@Inside Update Closed@@@'+setClosedTaskAccountIds);
                            }
                            else {
                                setOpenTaskAccountIds.add(Trigger.oldMap.get(t.Id).WhatId );
                                System.debug('@@@Inside Update Open@@@'+setOpenTaskAccountIds);
                            }
                        }
                    }
                }
            }
        }        
        if(Trigger.IsDelete){
            for(Task t : Trigger.Old){
                if(String.valueOf(t.WhatId).startsWithIgnoreCase('001')) {
                    if(t.Status.equalsIgnoreCase('Completed')){
                        setClosedTaskAccountIds.add(t.WhatId);
                        System.debug('@@@@Inside Deleted Completed');
                    }
                    else {
                        setOpenTaskAccountIds.add(t.WhatId);
                        System.debug('@@@@Inside Deleted Open');
                    }
                }
            }
        }            
        listOpenTaskAccounts =[SELECT Id, Name, Open_Task__c,(Select Status From Tasks Where Status != 'Completed' ) FROM Account WHERE Id =:setOpenTaskAccountIds];
        listClosedTaskAccounts =[SELECT Id, Name, Closed_Task__c,(Select Status From Tasks Where Status = 'Completed' )  FROM Account WHERE Id =:setClosedTaskAccountIds];
        System.debug('@@@@ListOpenTaskAccounts'+listOpenTaskAccounts );
        System.debug('@@@@ListClosedTaskAccounts'+listClosedTaskAccounts );       
        for(Account acc:listOpenTaskAccounts) {
            List<Task> listTask = acc.Tasks;
            acc.Open_Task__c = listTask.size();
            listAccountUpdate.add(acc);           
        }
        for(Account acc:listClosedTaskAccounts) {
            List<Task> listTask = acc.Tasks;
            acc.Closed_Task__c = listTask.size();
            listAccountUpdate.add(acc);           
        }
        try{
            System.debug('@@@@listAccountUpdate'+listAccountUpdate);
            update listAccountUpdate;
        }catch(System.Exception e){
            System.debug('@@@error'+e.getMessage());
        }
    }
}

Thanks.

Happy coding.