sql server 2008 r2 - The MERGE statement attempted to UPDATE or DELETE the same row more than once -

i have source table 3 fields

declare @tmptvp table ( id int, startdate datetime, enddate datetime )   insert @tmptvp values(1,'2013-04-28','2013-04-30') insert @tmptvp values(2,'2013-05-01','2013-06-30')  select * @tmptvp  target table 'insertdate' contains following data.  insert insertdate values(1,'2013-04-28','2013-06-30')  while merging merge (@tmptvp)  tgt using  (select id,startdate,enddate  @tmptvp)  src on (tgt.startdate = src.startdate or tgt.enddate = src.enddate)    when matched update set tgt.startdate = case when src.startdate < tgt.startdate  src.startdate else tgt.startdate end, tgt.enddate   = case when src.enddate > tgt.enddate  src.enddate else tgt.enddate  end,     when not matched  insert (id,startdate,enddate)    values (src.id,src.startdate,src.enddate); 

above merge statement throws merge statement attempted update or delete same row more once. happens when target row matches more 1 source row. merge statement cannot update/delete same row of target table multiple times. refine on clause ensure target row matches @ 1 source row, or use group clause group source rows.

can helps

please check site

http://www.sqlsafety.com/?p=665

the merge statement attempted update or delete same row more once. happens when target row matches more 1 source row. merge statement cannot update/delete same row of target table multiple times. refine on clause ensure target row matches @ 1 source row, or use group clause group source rows.” several times , forced run through query logic see has occurred. reading message self explanatory has happened. row in target table affected more once within merge statement causes query fail.

best regards