If you have an OUTPUT statement, this prevents data from being written to the dataset unless the OUTPUT is executed during this record's processing.

In this case the OUTPUT exists, but is never executed, so you have no data.

It's weird, but that's the way it is.

-----Original Message----- From: SAS(r) Discussion [mailto:SAS-L@LISTSERV.UGA.EDU] On Behalf Of Bian, Haikuo Sent: Friday, May 27, 2011 10:45 AM To: SAS-L@LISTSERV.UGA.EDU Subject: Help on Do While Loop!

Dear List,

Please check out following code:

data test; b=2; do while (b>3); output; end; run;

proc print; run;

There is no observation in "test" table after running. However, if you comment out "output", then there will be a record written into "test" table. Question: As we know that "Do While" evaluates expression at the top of the loop, and skips loop when expression is false, so why supposedly NON-executed "output" statement makes such a difference?

Thanks, Haikuo

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