Data files containing cross sections can be subsetted by controlling which cross sections to include in the output data set. Selecting a subset of cross sections is accomplished using the WHERE statement. The WHERE statement gives a condition that the BY variables must satisfy for a cross section to be selected. For example, the following statements extract the monthly market rate conversion factors for the United Kingdom (COUNTRY=’112’) and Switzerland (COUNTRY=’146’) for the period from September 1985 to February 1986.

filename datafile "imfifs1.dat" RECFM=F LRECL=88;

title3 'Time Series Defined in Selected Cross Sections';
proc datasource filetype=imfifsp
   outselect=on ebcdic
   interval=month
   out=ifs;

   where country in ('146', '112') and partner=' ';
   keep F___AA F___AC;
   range from '01sep85'd to '01feb86'd;
run;

title4 'OUTALL=IFS Data Set';
proc print
   data=ifs;
run;