To perform a self-join you just have to alias one or both tables.
In your case, you want to join on ( I guess) the SLM + CUST + ITEM,
restricting the tables to, respectively, 2003 and 2002. Further, you
want to filter out any rows where there's a match in 2002.
I believe the following does it:
s
Hi
Let me take a stab at it. I don't think you need a join at all. Check
the syntax but I think you can do it like this.
SELECT *,concat(slm,item,cust,year) as result1,concat(slm,item,cust,2003) as
result2 from sales where result1!=result2 AND date>2001
year would be taken from your date
