My Object Acount has a custom field ProfessionalReference__c

When i execute in developer : select id, type,  what.name from task : It's work

When I execute : select id, type, what.ProfessionalReference__c from task.
It doesn't work. Could you please explain ?


Thanks

My Object Acount has a custom field ProfessionalReference__c

When i execute in developer : select id, type,  what.name from task : It's work

When I execute : select id, type, what.ProfessionalReference__c from task.
It doesn't work. Could you please explain ?


Thanks