get all task related to contact in developer console [closed]

Question

I have creates a List of contacts in Salesforce UI and also created related tasks such as activity logs on those contact. Now I want to know how to fetch all the tasks related to those contacts. I have tried the following using execute anonymous in developer console:

List<Contact> conList  = [SELECT Id From Contact limit 5];
System.debug('--Task details with id ---' + conList);

But this doesn't show me the task objects, Please help me out on finding how to query out those tasks and their fields in apex code.

Answer 1

You will need to SOQL Contact first then feed the Tasks List with those ContactIds to get the related Tasks.

Contact SOQL

Contact[] cons = [SELECT id from Contact ];

Now, feed these ContactIDs to get related Tasks

Tasks

Task[] conTasks = [SELECT id, subject FROM Task WHERE Whoid in: cons];
System.debug('tasks:' + conTasks);

Answer 2

Additionally you can also use inner or outer join in SOQL to get Tasks based on Contact.

Outer join SOQL example:

SELECT Id, Subject FROM Task WHERE 
    WhoId IN (SELECT Id FROM Contact)

Inner join SOQL example:

for(Contact objContact: [SELECT Id, LastName, 
    (SELECT Id, Subject FROM Tasks) 
    FROM Contact]) {

    // Access Contacts through objContact
    for(Task objTask: objContact.Tasks) {
        // Access Tasks through objTask
    }
}