Definition of WHERE-Expression Processing

enables you to conditionally select a subset of observations, so that SAS processes only the observations that meet a set of specified conditions. For example, if you have a SAS data set that contains sales records, you might want to print just the subset of observations for which the sales are greater than $300,000 but less than $600,000. In addition, WHERE-expression processing can improve efficiency of a request. For example, if a WHERE expression can be optimized with an index, it is not necessary for SAS to read all observations in the data set in order to perform the request.

defines a condition that selected observations must satisfy in order to be processed. You can have a single WHERE expression, referred to as a simple expression, such as the following:

where sales gt 600000;

Or you can have multiple WHERE expressions, referred to as a compound expression, such as the following:

where sales gt 600000 and salary lt 100000;