для всей базы данных вы можете просто запустить эту
exec sp_helpdb 'YourDatabaseName'
за таблицу вы можете использовать это (2005 +)
declare @PageSize float
select @PageSize=v.low/1024.0 from master.dbo.spt_values v
where v.number=1 and v.type='E'
SELECT tbl.name,
ISNULL((select @PageSize * SUM(CASE WHEN a.type <> 1 THEN a.used_pages
WHEN p.index_id < 2 THEN a.data_pages ELSE 0 END)
FROM sys.indexes as i
JOIN sys.partitions as p ON p.object_id = i.object_id and p.index_id = i.index_id
JOIN sys.allocation_units as a ON a.container_id = p.partition_id
where i.object_id = tbl.object_id),0.0) AS [DataSpaceUsed_KB],
ISNULL((select @PageSize * SUM(a.used_pages - CASE WHEN a.type <> 1
THEN a.used_pages WHEN p.index_id < 2 THEN a.data_pages ELSE 0 END)
FROM sys.indexes as i
JOIN sys.partitions as p ON p.object_id = i.object_id and p.index_id = i.index_id
JOIN sys.allocation_units as a ON a.container_id = p.partition_id
where i.object_id = tbl.object_id),0.0) AS [IndexSpaceUsed_KB]
FROM
sys.tables AS tbl