Ok, I consider myself duly chastised.

By the way, what does SLA mean?

Thanks Craig, Jeff for pointing out the inefficiency. I didn't realize that using the aggregation like that would be so slow.

On the other hand the original question was: "How can...

For the original question, how about this:

[font="Courier New"]

select a.SomeDate,

(select max(b.SomeDate)

from #MyHead b

...