SOQL to get attachemnts

Question

i want to retrieve the attachments of SObject Account and also i was created a custom field(checkbox) named as is_read__c. Now, using SOQL is it possible to get attachments of Account from attachment SObject where condition is is_read__c = true

Answer 1

You can query for Accounts and Attachments in one Parent-Child SOQL Query.

SOQL:

List<Account> accounts = [Select Id, is_read__c, (Select Id from Attachments) from Account where is_read__c = true];

As commentators mentioned above you cannot add custom fields to the Attachment object.

http://www.salesforce.com/us/developer/docs/dbcom_soql_sosl/Content/sforce_api_calls_soql_relationships.htm