两个方法：
data have;
infile cards missover;
input id $ name $ age pid :$18. tnm $ entdat yymmdd10.;
format entdat yymmdd10.;
cards;
100194 ZTJ 61 . T1N0M0 2010-1-19
100194 ZTJ 61 120104195009182922 . 2010-6-12
100196 YZX . 12010519510913422X T2N1M0 2010-6-28
100878 YLY 50 . T3N1M0 2009-2-1
100890 DML . 120109550216302 T2N1M1 2009-8-18
;
run;
proc sort data=have;
by id entdat;
run;
/*方法1*/
data have1(keep=id pid);
set have;
where pid ne ' ';
run;
data have2;
set have;
by id;
if first.id;
run;
data want;
update have2 have1;
by id;
if pid ne ' ' then do;
  if length(pid)< 18 then age=year(entdat)-input('19'||substr(pid,7,2),4.);
  else age=year(entdat)-put(substr(pid,7,4),4.);
end;
run;
proc print;
run;
/*方法2*/
proc sql;
create table have3 as select id, name, age, max(pid) as  pid,
max(tnm) as tnm,entdat
from have
group by id;
quit;

data want;
set have3;
by id;
if first.id;
if pid ne ' ' then do;
  if length(pid)< 18 then age=year(entdat)-input('19'||substr(pid,7,2),4.);
  else age=year(entdat)-put(substr(pid,7,4),4.);
end;
run;
proc print;run;

数据库  不懂         

个人思路，subset出身份证号码PID 来得到Entage,可以区分15位还是18位的不同算法得到age
pro sql把新的dataset join回source，
keep TNM不为空的数据，
如果Entage不为空，age=Entage；如果Entage为空，Entage=age
drop age; proc sort, 保留不重复的应该就是想要的结果了

PROC IMPORT OUT= WORK.mingyue
            DATAFILE= "D:\mingyue.xls"
            DBMS=EXCEL REPLACE;
       GETNAMES=YES;
     MIXED=NO;
     SCANTEXT=YES;
     USEDATE=YES;
     SCANTIME=YES;
RUN;
data mingyue;
set mingyue;
if length(pid)=15 then do;
part1=substr(pid,1,6);
part2=substr(pid,length(pid)-8,9);
newpid=compress(part1||'19'||part2||'X');
end;
if length(pid)=18 then newpid=pid;
birth=input(compress(substr(newpid,7,8)),yymmdd11.);
format birth yymmdd10.;
if pid ne '.' then entage=int(yrdif(birth,entdat,act/act));
if pid='.' then entage=age;
run;
proc sql;
create table newtable as select  distinct caseid, name,entage,   max(PID) as pid,  max(TNM) as TNM from mingyue
group by caseid;
quit;

如果可以的话，希望能写出完整的语句，非常感谢，^_^