SAS Certification Prep Guide, 4th Edition

Writing Observations Explicitly

To override the default way in which the DATA step writes observations to output, you can use an OUTPUT statement in the DATA step. Placing an explicit OUTPUT statement in a DATA step overrides the automatic output, so that observations are added to a data set only when the explicit OUTPUT statement is executed.

Syntax, OUTPUT statement: OUTPUT <SAS-data-set(s)>; SAS-data-set(s) names the data set or data sets to which the observation is written. All data set names that are specified in the OUTPUT statement must also appear in the DATA statement. Using an OUTPUT statement without a following data set name causes the current observation to be written to all data sets that are specified in the DATA statement. ...