SAS Certification Prep Guide, 4th Edition

Modifying Observations Using a Transaction Data Set

Overview

You can use a MODIFY statement to update all observations in a data set, but there are times when you want to update only selected observations. You can modify a master SAS data set with values in a transaction data set by using the MODIFY statement with a BY statement to apply updates by matching observations.

General form, MODIFY statement with a BY statement: DATA SAS-data-set; MODIFY SAS-data-set transaction-data-set; BY key-variable; RUN; Here is an explanation of the syntax: SAS-data-set is the name of the SAS data set that you want to modify (also called the master data set). transaction-data-set is the name of the SAS data set with updated values. key-variable ...