J: Let me add a few comments to the good advice that you have already received. Missing and NULL values in SAS cause the same mischief that they cause elsewhere in the database programming world. Repeating groups of variables and other sins in the normalized database religion create missing and NULL values as placeholders. In my opinion, too much time goes into managing them.

In SAS SQL and most other flavors, the logical expression 'var IS NULL' evaluates as TRUE when var has a missing or null value and 'NOT var IS NULL' has the opposite value for the same value of variable var. This form of logical expression evaluates different data types equally well.

Of course beware of comparisons of NULL values in SQL. var=var evaluates to NULL when var IS NULL, not TRUE. var^=var also evaluates to NULL when var IS NULL, not to FALSE as you might expect. This trinary logic has its uses and pitfalls. S

-----Original Message----- From: owner-sas-l@listserv.uga.edu [mailto:owner-sas-l@listserv.uga.edu] On Behalf Of J Sent: Tuesday, July 17, 2007 11:04 PM To: SAS-L@LISTSERV.UGA.EDU Subject: Proc Sql.. want to use or.. but doens't work!

I want to use the following proc sql

libname mylib '\\somedirectory\folder\';

proc sql; create table mylib.output as select * from mylib.dataset where variable1 = '.' or variable2 = '.' or variable3 ='.'; quit;

Is there anything I can do where I can create a dataset w/ or operators?