How to Count Number of Records in Related List and Display in Parent object Layout (Using Trigger) ?

How to Count Number of Records in Related List of Parent object and How to Display the Result in Parent Object Field (Using Apex Trigger) ?

Hi Guys,

After a long time i am here to share one post with you..

Here, I am Posting one Code for Counting No. of Records in Related list of Parent object and Display that Result in Custom field of Parent object..

Let's say i am counting here Number of Contact (Child) which is related to one Account (Parent)...

APEX TRIGGER CODE :

trigger countContact on Contact (after insert,after update) {

     Set<String> AccId = new Set<String>();

     

     List<Account> acc= new List<Account>();

     

     //Store the Temporary Account Id of the Child Contact

     for (Contact c1 : Trigger.New) {

        if (c1.AccountId != null) {

            AccId.add(c1.AccountId);

        }

    }

     

     // Functionality to Count Number of Contact available in Related Account

     for(Contact c : Trigger.New){

     

         List<AggregateResult> con =[SELECT AccountId aId, Count(Id)countContact FROM Contact WHERE AccountId IN : AccId GROUP BY AccountId];

         

         Integer contactCount = (Integer)con[0].get('countContact');

         

         System.debug('contact Count is ='+contactCount);

         

         // Store or Display Result of Counting Contact to Account's custom Field in Account Page Layout

         Account a = new Account();

         a.Id = (Id)con[0].get('aId');

         a.Contact_count__c = (Integer)con[0].get('countContact');

         acc.add(a);

         

     }

     

     update acc;

}

Cheers !!!!