select 
  schema_name(tab.schema_id) as [schema_name], 
  tab.[name] as table_name 
from 
  sys.tables tab 
  left outer join sys.indexes pk on tab.object_id = pk.object_id 
  and pk.is_primary_key = 1 
where 
  pk.object_id is null 
order by 
  schema_name(tab.schema_id), 
  tab.[name]