I am trying to identify "valid" defaulted borrowers from the default listing span from 2012 to 2019. If a borrower re-default within the default's tracking period (win_end_date) then that particular default observation need to be removed. On contrary, If a borrower redefault after expiry of tracking period then that default event will be recognised as "valid" again.      Here is my sample and expected results:   Raw Data       Cust_NO DEF_DATE Win_End_Date Remark 10106212 31-Dec-12 31-Dec-14 1st Default (tracked performance up to 24 momths) 10106212 31-Dec-13 31-Dec-15 Overlapped with 1st Default  tracking period (Re-Defaulted  within tracking periods of 1st Default) 10106212 31-Dec-14 31-Dec-16 Overlapped with 1st Default  tracking period (Re-Defaulted  within tracking periods of 1st Default) 10106212 31-Dec-15 31-Dec-17 2nd Default (happen after expiry of tracking period of 1st Default) 10106212 31-Dec-17 31-Dec-19 Overlapped with 2nd Default  tracking period (Re-Defaulted  within tracking periods of 2nd Default) 10106212 31-Dec-18 31-Dec-20 3rd Default 10378803 30-Jun-14 30-Jun-16 1st Default 10378803 31-Dec-15 31-Dec-17 Overlapped with 1st Default  tracking period (Re-Defaulted  within tracking periods of 1st Default)         Expected Output       Cust_NO DEF_DATE Win_End_Date   10106212 31-Dec-12 31-Dec-14   10106212 31-Dec-15 31-Dec-17   10106212 31-Dec-18 31-Dec-20   10378803 30-Jun-14 30-Jun-16   ... View more

I have the following data set, which i wish to get the final maturity date (maturity_Date_1) for the roll over transaction(condition-  if (maturity date - subsequent issue date) fell between 0 and 1, then considered as roll over transaction).I have been struggling for sometimes, but still not able to come up with the codes. Is it possible to use lag function and Do looping ?   Please advise how to write the coding in SAS to obtain the final maturity date (Maturity Date_1) from maturity date for all customers. Remarks is not as port of the output.     Cust_NO number  Amount  Issue_Date  Maturity_Date   Maturity_date_1 Remarks B           1   10000   08-Sep-14   08-Dec-14                             08-Jun-15   Roll over B           2   10000   08-Sep-14   08-Dec-14                             08-Jun-15   Roll Over B           3   10000   08-Dec-14   09-Mar-15                                            .   Roll over from 1 B           4   10000   08-Dec-14   09-Mar-15                                            .   Roll over from 2 B           5   10000   09-Mar-15   08-Jun-15                                            .   Roll over from 3 B           6   10000   09-Mar-15   08-Jun-15                                            .   Roll over from 4 A           1   20000   29-Sep-16   28-Oct-16                             24-Apr-17   Roll over A           2   20000   28-Oct-16   28-Nov-16                                            .   Roll over from 1 A           3   20000   28-Oct-16   28-Nov-16                            28-Nov-16   Distinct Transaction A           4   20000   28-Nov-16   29-Dec-16                                          .   Roll over from 2 A           5   20000   29-Dec-16   27-Jan-17                                          .   Roll over from 4 A           6   20000   26-Jan-17   27-Feb-17                                          .   Roll over from 5 A           7   20000   27-Feb-17   24-Mar-17                                         .   Roll over from 6 A           8   20000   24-Mar-17   24-Apr-17                                          .   Roll over from 7   Thanks ... View more