/****** Скрипт для команды SelectTopNRows из среды SSMS  ******/
set dateformat dmy    
declare @sdate datetime    
set @sdate='01/01/2012' -- дата до которой все записи будут удалены    

delete from [BN_PATP].[dbo].[PATP_Events] where id in (
     select EV.id from [BN_PATP].[dbo].[PATP_Events] as Ev with(readcommitted, tablock)    
     left join [BN_PATP].[dbo].[PATP_OrderDataDay] as ODD on ODD.id=Ev.Order_Data_day_id
     where (Ev.event_time<@sdate and Ev.Order_Data_day_id is null) or (ODD.[day_date]<@sdate)
   )