Hi ... you can try this ...   * create a data file (no data set created); data _null_; * specify the name of the data file; file 'c:\new.txt'; * create some numeric variables and give them all a value of 99; retain x1 x2 x3 99; * write the values of the variables to the file specified in the FILE statement; put x1-x3; run;   * read the data file you just created and create a data set; data new; * specify the location of the data file; infile 'c:\new.txt'; * read the data; input x1-x3; run;   * look at your data set; proc print data=new; run;   Another way to remember the difference between FILE and INFILE is to think of the statements PUT and INPUT.  PUT statements are associated with FILE (write to a file) and INPUT statements are associated with INFILE (read data from an already existing file). ... View more

data have; input Acc_No Transaction_Date date8. Transaction_Amount ; format Transaction_Date date9.; datalines; 100 1-Jul-15 1000 100 2-Jul-15 2000 100 3-Jul-15 3000 100 4-Jul-15 4000 100 5-Jul-15 5000 101 6-Jul-15 6000 101 7-Jul-15 7000 101 8-Jul-15 2500 101 9-Jul-15 500 ; data want;   set have;   by Acc_No;   if lag(first.Acc_No);   putlog Transaction_Date; run; 02JUL2015 07JUL2015 Add a where clause if you need one customer only. ... View more