Dubbele records combineren in SQL Server

Twee stappen:1. update de records met de juiste locaties, 2. verwijder de records met de verkeerde locaties.

update mytable
set onhand = onhand + 
(
  select coalesce(sum(wrong.onhand), 0)
  from mytable wrong
  where wrong.location like ' %'
  and trim(wrong.location) = mytable.location
)
where location not like ' %';

delete from mytable where location like ' %';