Reducing Dataset to minimum records

[rahul11124]

This works but not the efficient one if we run this code on millions of row it will generate around 365 date for each row in do loop

[Ksharp]

OK. How big table do you have ?

If you really care about efficiency problem , try this one .

data have;
input Coverage_Start : date11. Termination_Date : date11. Member_Id;
format Coverage_Start  Termination_Date  date11. ;
cards;
24-Jul-19 1-Jun-21 42968701
24-Jul-19 1-Mar-21 42968701
29-Feb-20 1-Mar-20 42968701
16-Feb-19 1-Mar-19 42968701
1-Mar-17 1-Mar-18 42968701
1-Mar-16 1-Mar-17 42968701
1-Dec-15 31-Dec-16 42968701
;

data want;
 array date{99999} _temporary_ ;
do until(last.Member_Id);
 set have;
 by Member_Id;
 do i=Coverage_Start to Termination_Date;
   date{i}=1;min=min(min,i);max=max(max,i);
 end;
end;
 do i=min to max;
  if missing(date{i-1}) and not missing(date{i}) then start=i;
  if missing(date{i+1}) and not missing(date{i}) then do;end=i;output;end;
 end;
call missing(of date{*});
 format start end date11.;
 keep Member_Id start end;
run;