Query return different data count

Question

When I run

select count() from attachment ; it returns 3099 .

when I run

Select Name,Id,ParentId,Parent.Type,Owner.Name,Owner.Id ,Owner.IsActive ,ContentType,isPrivate from Attachment ; it return 3099

when I run

Select count(Parent.Type) from Attachment ; -- it return 3091

when I run

Select Name,Id,ParentId,Parent.Type,Owner.Name,Owner.Id ,Owner.IsActive ,ContentType,isPrivate from Attachment order by Parent.Type; it return 3050

I played with SOQL above today and I have no idea why it returns data count differently.Which one is accurate?

The aggregate value still return null but total count is different between select count() from attachment.

Answer 1

1st and 2nd query returns number of attachments, 3rd query is returning attachments having Parent.Type != null so you are getting count different

Answer 2

After I digged the all the data return by select Id from Attachment, I found out the missing number is coming from Parent.type='00X' which are Unfiled Public Email Templates.

https://unidha-dev-ed.my.salesforce.com/00X?setupid=CommunicationTemplatesEmail&retURL=%2Fui%2Fsetup%2FSetup%3Fsetupid%3DCommunicationTemplates

However if we try to manually query it

Select Id from Attachment where Parent.Type='00X , it will return 0 data.

Also some of Parent.Type is null but actually it is 'Event'.

I hope they have documentation on this.