%macro updatetable(Cardnum=,AfterUpdateBal=);
proc sql;
update Cards
set Bal=&AfterUpdateBal.
where Card_num="&Cardnum.";
quit;
%mend;
%macro repay(Cardnum=);
proc sql;
update Cards
set Bal=LIMIT_AMT
where Card_num="&Cardnum.";
quit;
%mend;
data trans;
do i=1 to 100;
mycardpoint=CEIL(RANUNI(0)*mycardnobs);
set Cards POINT=mycardpoint nobs=mycardnobs; /*随机取一张卡*/
Tx_Amt=1000*rand('uniform'); /*随机产生一个消费金额*/