Specifying the most recently created data set to use in a read operation

By default, the _LAST_= system option is set to use the most recently created data set. This automatic feature is commonly found in procedure code when the DATA= option is omitted from a PROC.

 To override this built-in default, the _LAST_= system option can be defined as any valid temporary or permanent SAS data set name (refer to data set naming conventions).

The _LAST_= option can be specified in an OPTIONS statement, in the OPTIONS window, at SAS invocation, or in the configuration file.