I have a table that includes a customer name and the difference (in months) between two dates. I need a macro that, based on the number of months in between the two dates, adds that determined amount of rows.   Basically, my table has 4 columns: Customer Name, Date 1, Date 2 and Months. Months refers to the difference in Months between Date 1 and Date 2. Again, my objective is to add rows below each customer. Number of rows to be added should depend on the number of "Months".   I tried building some code myself but ir takes forever to run. I am using SAS Enterprise Guide version 7.13   Looking for some smart suggestions on how I can create a more efficient method. Table has about 200,000 rows and last time I tried running it, it took more than 8 hours. Any thoughts?   Here's my attempt:     proc sql noprint; select max(monotonic()) into : num_rows from work.table_template ; quit;   %put Number of rows is: &num_rows.; options mprint merror mlogic symbolgen;   %macro one; %do i = 1 %to &num_rows.; data _null_; set work.table_template; if _n_ = &i.; call symputx('Customer_Name',Customer_Name); call symputx('Date1',Date1); call symputx('Date2',Date2); call symputx('Months',Months); run; %do j = 2 %to (&months.-1); data _null_; call symputx('Date1',intnx('month',&Date1.,1)); run;   proc sql; insert into work.table_template values ("&Customer_Name.",&Date1.,&Date2.,&Months.); quit; %end; %end; %mend one; %one; ... View more