I'd to match-merge 2 tables in such a manner that I keep all the rows in table 1, but not the rows that are in both table 1 and 2.
Thank you for your help,
Alfredo

> master <- data.frame(ID=2001:2011)
> train   <- data.frame(ID=2004:2006)
> valid <- ???

in this example table valid should have the following

> str(valid)
 Year: int  2001 2002 2003 2007 2008 2009 2010 2011

in SAS I'd do the following:
data master; do id=2001 to 2011; output; end; run;
data train; do id=2004 to 2006; output; end; run;
data valid; merge master(in=a) train(in=b); by id; if a and not b; run;

and in SQL:
create table valid as
  select a.* from master where ID not in (select ID from train)



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