SOQL-如何获取组合附件的父名称

Question

I am unable to obtain the Name of a Parent object, where the child is CombinedAttachments. The SOQL I use is listed below and works as expected.

SELECT ( SELECT Id, Title, RecordType, LastModifiedDate, CreatedBy.Name, ParentId from CombinedAttachments WHERE ParentId = '001b0000009ovxS' ORDER BY LastModifiedDate DESC limit 100 ) FROM Account WHERE Id = '001b0000009ovxS'

What is impossible is to add a filed like Parent.Name or Parent.Account.Name. However, in other cases of Parent-Child queries like that, it is straightforward to refer to Parent fields by using dot notation like Parent.CaseNumber or Who.Name It seems that due to the fact that there may be multiple references possible in ParentID (Account,Asset,Campaign,Case,Contact,Contract,EmailTemplate,Event,Lead,Opportunity,Product2,Solution,Task)

Answer 1

With a polymorphic relationship field, such as CombinedAttachments.ParentId , the field can reference a large number of types.

In this case you can only select a subset of fields that are common to all the types being referenced.

You will need to do secondary queries to Account to pull the required fields.

Alternatively, you might be able to reverse the join to get the Account fields, but you have now lost the CombinedAttachments fields.

SELECT Id, Name
FROM Account
WHERE Id IN (Select ParentID from CombinedAttachments)

As an aside, there is a dedicated Salesforce StackExchange site for Salesforce questions.

Answer 2

One tested approach is to use the Parent field name in the parent side rather then refer to it from the sub-query:

SELECT Name, Id, ( SELECT Id, Title, RecordType, LastModifiedDate, CreatedBy.Name, ParentId from CombinedAttachments WHERE ParentId = '001b0000009ovxS' ORDER BY LastModifiedDate DESC limit 100 ) FROM Account WHERE Id = '001b0000009ovxS'