contact count on account trigger
trigger CountContactOnAccount on Contact (after INSERT, after UPDATE, after DELETE ) {
Set <Id> accountIds = new Set <Id>();
List <Account> lstAccountsToUpdate = new List <Account>();
if(Trigger.isInsert){
for(Contact con:trigger.new){
accountIds.add(con.accountID);
}
}
if(Trigger.isUpdate|| Trigger.isDelete){
for(Contact con:trigger.old){
accountIds.add(con.accountID);
}
}
for(Account acc:[SELECT Id,Name,Count_Contact__c,(Select Id from Contacts) from Account where Id IN: accountIds]){
Account accObj = new Account ();
accObj.Id = acc.Id;
accObj.Count_Contact__c = acc.Contacts.size();
lstAccountsToUpdate.add(accObj);
}
UPDATE lstAccountsToUpdate;