Handling Zero Results SOQL on Attachments

Question

I have a controller that sends an email and grabs a few different attachments from different records.

Not all the records will have an attachment called 'Venue Map' so I want to stop the error if the SOQL returns null. Not sure what to do here.

    Attachment att = [
         select name, contenttype, body
         from Attachment
         where name LIKE '%Venue Map%' and ParentId = :cf.courses__r.venueid__c][0];

    if(att.body.size() > 0 ){
    Messaging.Emailfileattachment MyMap = new 
    Messaging.Emailfileattachment();
    MyMap.setContentType(att.contentType);
    MyMap.setFileName('Venue Information.pdf');
    MyMap.setBody(att.Body);
    fileAttachments.add(MyMap);
    }     

    mail.setFileAttachments(fileAttachments);

The code is working perfect when there is a 'Venue Map' attachment, but if there isnt it just gives me this error "List index out of bounds: 0"

Answer 1

I suggest before using indexing of [0]. first, query and store into the list and then check if the size is more than 0 then perform everything like below

List<Attachment> attachments = [select name, contenttype, body
                                  from Attachment
                                 where name LIKE '%Venue Map%' 
                                   and ParentId = :cf.courses__r.venueid__c];
if(attachments.size() > 0){
    att = attachments[0];

   if(att.body.size() > 0 ){
       Messaging.Emailfileattachment MyMap = new 
       Messaging.Emailfileattachment();
       MyMap.setContentType(att.contentType);
       MyMap.setFileName('Venue Information.pdf');
       MyMap.setBody(att.Body);
       fileAttachments.add(MyMap);
   }     

    mail.setFileAttachments(fileAttachments);
}