SQL Server, getting the size of table partitions with T-SQL

Needed to quickly tell someone how large the partitions on a CRM 2011 auditbase table were (neither of us had access to the nice CRM GUI to answer it (ah they joys of not being trusted!)). So if anyone else needs some thing similar this is what I came up with:

SELECT
part.partition_number,
sum(alloc.total_pages/128) AS TotalTableSizeInMB,
sum(alloc.used_pages/128) AS UsedSizeInMB,
sum(alloc.data_pages/128) AS DataSizeInMB
FROM sys.allocation_units AS alloc
INNER JOIN sys.partitions AS part ON alloc.container_id = CASE WHEN alloc.type in(1,3) THEN part.hobt_id ELSE part.partition_id END
LEFT JOIN sys.indexes AS idx ON idx.object_id = part.object_id AND idx.index_id = part.index_id
where part.object_id = object_id('auditbase')
group by partition_number

If you compare the numbers with thos provided by CRM you’ll notice a differece:

And that’s just because Dynamics CRM doesn’t include the space the indexes take up.