Creating multiple observations based on multiple other ones - database

Question

I am trying to find a way to create observations based on multiple other ones using SAS.
For example, I have the following table:
+------+--------------------+-------------------+
| ID | START_DATE | END_DATE |
+------+--------------------+-------------------+
| ABC1 | 01FEB201500:00:00 | 30NOV201600:00:00 |
| ABC1 | 01JAN201700:00:00 | 30NOV201800:00:00 |
+------+--------------------+-------------------+
And I would like to create a table where all the timestamps for the period 01JAN2014 to 31DEC2020 are covered. In other words, it would consist of creating 2 more observations to the dataset to look like this;
+------+--------------------+-------------------+
| ID | START_DATE | END_DATE |
+------+--------------------+-------------------+
| ABC1 | 01FEB201400:00:00 | 31JAN201500:00:00 |
| ABC1 | 01FEB201500:00:00 | 30NOV201600:00:00 |
| ABC1 | 01DEC201600:00:00 | 30NOV201800:00:00 |
| ABC1 | 01DEC201800:00:00 | 31DEC202000:00:00 |
+------+--------------------+-------------------+
The SAS code to re-create this example is:
DATA test;
INPUT ID :$4. START_DATE :datetime18. END_DATE :datetime18.;
FORMAT START_DATE datetime20. END_DATE datetime20.;
CARDS;
ABC1 01FEB201400:00:00 31JAN201500:00:00
ABC1 01JAN201700:00:00 30NOV201800:00:00
;
RUN;
I don't see a way to do this in SAS

Answer 1

You can fill in (or compute) intra range gaps using basic comparisons, some holding variables and a retained variable.
Example:
Presume no ranges overlap and are order low start first.
data have;
input id x1 x2; datalines;
1 3 7
1 11 14
2 4 9
2 15 18
3 1 11
4 11 20
5 1 2
5 3 4
5 5 9
5 10 20
;
data want;
set have;
by id;
length type $6;
* fill in ranges for every integer 1 through 20;
if first.id then do;
bot = 1;
retain bot;
end;
if bot < x1 then do;
hold1 = x1;
hold2 = x2;
x1 = bot;
x2 = hold1 - 1;
type = 'gap -';
output;
x1 = hold1;
x2 = hold2;
type = 'have';
bot = x2 + 1;
output;
end;
else if x1 <= bot <= x2 then do;
bot = x2 + 1;
type = 'have';
output;
end;
if last.id and 20 >= bot > x2 then do;
type = 'gap +';
x1 = bot;
x2 = 20;
output;
end;
keep type id x1 x2 bot;
run;