I knew I couldn't do it in the GROUP BY, but I don't know why it's not allowed in the WHERE. And, I knew I could do it by...

Don't really know. The BOL says that in the absence of a GROUP BY, the HAVING acts as a WHERE. Doesn't in practice, though. I just thought...

Thanks for your reply, Tomm. But you seem to be missing the point of the GROUP BY -- the idea is if I have, say 5 topics, I want...

Can you post a sample ddl with some data?

Aaron, that's an interesting approach. Basically, you're appending the data you want to use to the end of the field you're sorting on. Once sorted, you simply break...

It's interesting you did not point out the possibility of a "double unknown" of using this method. That is, it's possible for the error field to be either 0...

You're right; I found how to do that. However, is there any way to do the thing in my example -- introspectively get data from the table at...

Yes, it is sort of recursive. In the example, every new row will have the number of rows currently in the database (might go up, might go down). ...

Basically, what I said was it's historic data and I can't delete it. The only thing it has in common is that, for a given key, each line updates...

well, I had a nice long reply... but the forum ate it.

can you post an example?

What's the nature of your input?

As a test, I refactored the CTE as a variable, and it close to doubled the execution time.

Is there a way to use a CTE to create another CTE?

Alright, try this:

DECLARE @data TABLE(
lname VARCHAR(40)
,fname VARCHAR(40)
,val INT
,perf DECIMAL(9,4)
,retrn DECIMAL(9,4)
)

INSERT @data VALUES('Jones','Adam',55,1.234,2.023)
INSERT @data VALUES('Jones','Adam',56,2.235,-0.321)
INSERT @data VALUES('Jones','Adam',57,0.034,3.232)
INSERT @data VALUES('Jones','Adam',58,-0.989,6.444)
INSERT @data VALUES('Jones','Adam',59,3.334,-1.822)
INSERT @data VALUES('Smith','Benny',56,4.004,1.923)  
INSERT @data VALUES('Smith','Benny',58,2.031,2.176)
INSERT @data VALUES('Smith','Benny',59,-0.003,1.332)
INSERT @data VALUES('Tyler','Tom',55,0.002,0.012)
INSERT...

Can you post a ddl & sample data?