fixed invalid query to Salesforce when there is no record

lib/sf/account.rb

@@ -100,8 +100,12 @@ def self.inc_parts_to_be
 
   def self.inc_certs_to_be
     acct_ids = Sf::Opportunity.cert_subscribers(Date.today.prev_month(2)).map(&:AccountId)
-    accts_str = acct_ids.map{|v| "\'#{v}\'"}.join(', ')
-    build_collection Sf.client.query("select #{FIELDS_SELECT_STR} from Account where InCommon_Participant__c = true and Id in (#{accts_str})")
+    if acct_ids.empty?
+      []
+    else
+      accts_str = acct_ids.map{|v| "\'#{v}\'"}.join(', ')
+      build_collection Sf.client.query("select #{FIELDS_SELECT_STR} from Account where InCommon_Participant__c = true and Id in (#{accts_str})")
+    end
   end
 
   def self.active_inc_parts(service_name)

lib/sf/version.rb

@@ -1,3 +1,3 @@
 module Sf
-  VERSION = "0.1.34"
+  VERSION = "0.1.35"
 end