SAS Macro Do Loop not resolving -

can tell me why isn't resolving:

/*put transaction table names data set*/  /*(table names of format transac_20130603_20130610 (date , date to)*/ data transaction_tables;     set sashelp.vtable (keep=libname memname);     lowcase(substr(memname,1,8))='transac_'  run; /*sort , add rownumbers*/ proc sql; create table transaction_tables     select *, monotonic() rownum          transaction_tables              order memname; run; /*find rownumber of first , last transaction tables run dates before campaign start , after end date of campaign*/ data _null_; set transaction_tables;     if substr(memname,9,8)<=&pre_period_start. , substr(memname,18,8)>=&pre_period_start. do;         call symput("r1", rownum);         stop;          end; run;         data _null_; set transaction_tables;     if substr(memname,9,8)<=&max_enddate. , substr(memname,18,8)>=&max_enddate. do;         call symput("r2", rownum);         stop;         end; run; %put &r1; %put &r2; /*r1 = 11, r2 = 27 - both resolving ok*/  /*get relevant transaction table names rownumbers between r1 , r2*/ /*r1=11 , r2=27 transaction table name macros should run t_0 t_16/* %macro trans; %let y = %eval(&r2 - &r1); %do i=0 %to &y; data _null_; set transaction_tables;     if rownum = &r2 - (&r2 - &r1 - &i)  do;         call symput("t_&i", cats(libname, '.', memname));         stop;          end; %end; %mend trans; %trans;  %put &t_0; --warning: macro variable "&t_0" not resolved 

i'm not entirely sure why messing around few of variables think problem lies last part attempting assign table names t_&i macros. think issue trying name macro variable while trying call macro variable (trying create macro t_0 calling &i when i=0). guess i've screwed syntax because think logic sound.

thanks!

without judging usefulness of you're trying do:

it scope issue. macro variable create within macro, exists within macro. if want exist outside macro, either need to:

• create macro variable in open code (not in macro) , before execute macro.

• set explicitly global within macro (before first mention of it), writing:

  %global t_0;

edit note end proc sql, need use quit instead of run.