trigger AccountDeletion on Account (before delete) {
   
    // Prevent the deletion of accounts if they have related opportunities.
    for (Account a : [SELECT Id FROM Account
                     WHERE Id IN (SELECT AccountId FROM Opportunity) AND
                     Id IN :Trigger.old]) {
        Trigger.oldMap.get(a.Id).addError(
            'Cannot delete account with related opportunities.');
    }
    
}

Can somebody provide a sample code to have a debug log in the For loop, so I can know what are the parameters get passed.
or is there any way the SOQL query to be passed to a string so I can see what's going on.

Thanks,
James George