一、数据集添加序号

方法1：data步生成
方法2：proc sql生成

/** 方法1 **/
data class1; 
  set sashelp.class; 
  seq = _N_; /** 添加序号 **/
run;  

/** 方法2 **/
proc sql;
  create table class2 as 
  select monotonic() as id, *  /** monotonic()添加id **/
  from sashelp.class ;
quit;

二、同一ID多条观测加序号

第一步：排序 proc sort
第二步：first语句、累加

data t1;
input id name$ sex$ age subject$ score;
cards;
1001 Tom F 25 Chinese 80
1001 Tom F 25 Math 72
1001 Tom F 25 English 90
1003 Lisa M 20 Chinese 65
1003 Lisa M 20 Math 93
1005 Anna M 26 Chinese 93
1005 Anna M 26 Math 70
1002 Lyli M 21 Chinese 85
;
run;
proc print data=t1;run;

proc sort data=t1; by id subject; run;

data t2;
 set t1;
  by id subject ;   /* 与排序的变量一致 */
  retain SEQ;
  if first.id then SEQ = 1 ;   
  else SEQ = SEQ +1 ;
run;
proc print data=t2;run;