标题: try this one [打印本页] 作者: shiyiming 时间: 2005-10-27 00:51 标题: try this one proc sort data=tem; by id date; run;
data tem_r(keep=id sdate edate new_vol);
set tem;
by id;
retain this_date;
format sdate edate yymmdd10.;
lag_id=lag(id);
lag_vol=lag(vol);
lag_date =lag(date);
if first.id then this_date=date;
else do;
if lag_vol^=vol then do;
id =lag_id;
edate=lag_date;
new_vol=lag_vol;
sdate=this_date;
this_date=date;
output;
end;
end;
if last.id then do;
sdate=this_date;
new_vol=vol;
edate=date;
output;
end;
run;