Can I use CASE statement in a JOIN condition?

Question

The following image is a part of Microsoft SQL Server 2008 R2 System Views. From the image we can see that the relationship between sys.partitions and sys

Answer 1

I took your example and edited it:

SELECT  *
FROM    sys.indexes i
    JOIN sys.partitions p
        ON i.index_id = p.index_id 
    JOIN sys.allocation_units a
        ON a.container_id = (CASE
           WHEN a.type IN (1, 3)
               THEN p.hobt_id 
           WHEN a.type IN (2)
               THEN p.partition_id
           ELSE NULL
           END)