Random sample

[Bill Wu]

  I try to randomly select 200 cases from 1000 and each time I will get
the same cases. Is there anyway I can select different cases at
different times?

Bill

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[Bruce Weaver]

Bill Wu wrote

  I try to randomly select 200 cases from 1000 and each time I will get
the same cases. Is there anyway I can select different cases at
different times?

Bill

You must have the same SEED value every time.  This is from the Help for "SET (command), SEED subcommand":

SEED={integer | RANDOM}  Initialization value for MC random number generator. The value must be a positive integer that is less than 2,000,000,000 or the keyword RANDOM, which randomly sets the initialization value. The default is 2,000,000.

Try this:

SET SEED = RANDOM.

Then select your random sample.