Count, Group by between dates

Question

I am trying to count the number of IDs dropped and enrolled in each unit for each of the 4 terms between their perspective dates.
There are 4 Terms and an ID can participate in a unit in any of these terms:
TERM
START_DATE
END_DATE
1
25-Feb-13
18-Mar-13
2
27-May-13
17-Jun-13
3
26-Aug-13
16-Sep-13
4
25-Nov-13
16-Dec-13
I am trying to count how many IDs enrolled in a unit between those dates and how many doped before the end date
The ENROL_DATE for each ID in a unit has to be between the given Term Dates to count.
Unit KIS has 1 ENROL and one DROP in TERM 1
UNIT POL occurs in TERM 2 and 4 and both DROP
UNIT LIN and 1 ENROL and 1 DROP in 2 different TERMS
My problem is how do i specify count ENROL and count drop between the Term dates and then group by TERM and UNIT.
Please see below table for given data and expected result. It should make sense.
Thanks,
{code}
CREATE TABLE DAN_GR4
(ID             NUMBER(12),
STATUS           VARCHAR2(12),
TERM             NUMBER(12),
ENROL_DTE       DATE,
TERM_START_DTE  DATE,
TERM_END_DATE   DATE,
UNIT            VARCHAR2 (12));
INSERT INTO  DAN_GR4 (ID,STATUS,TERM,ENROL_DTE,TERM_START_DTE,TERM_END_DATE,UNIT) VALUES ('1',    'ENROL'    ,'1',    '15-Mar-13'    ,'25-Feb-13' ,'18-Mar-13',  'KIS');
INSERT INTO  DAN_GR4 (ID,STATUS,TERM,ENROL_DTE,TERM_START_DTE,TERM_END_DATE,UNIT) VALUES ('1',    'DROP'    ,'2',    '27-MAY-13'    ,'27-MAY-13' ,'17-JUN-13',    'POL');
INSERT INTO  DAN_GR4 (ID,STATUS,TERM,ENROL_DTE,TERM_START_DTE,TERM_END_DATE,UNIT) VALUES ('1',    'DROP'    ,'2',    '27-JUN-13'    ,'27-MAY-13' ,'17-JUN-13',    'LIN');
INSERT INTO  DAN_GR4 (ID,STATUS,TERM,ENROL_DTE,TERM_START_DTE,TERM_END_DATE,UNIT) VALUES ('1',    'DROP'    ,'3',    '27-JUN-13'    ,'27-MAY-13' ,'17-JUN-13',    'PUI');
INSERT INTO  DAN_GR4 (ID,STATUS,TERM,ENROL_DTE,TERM_START_DTE,TERM_END_DATE,UNIT) VALUES ('2',    'DROP'    ,'3', '26-SEP-13'    ,'26-AUG-13' ,'16-SEP-13',    'POL');
INSERT INTO  DAN_GR4 (ID,STATUS,TERM,ENROL_DTE,TERM_START_DTE,TERM_END_DATE,UNIT) VALUES ('2',    'ENROL'    ,'4',    '26-NOV-13'    ,'25-NOV-13' ,'16-DEC-13',    'LIN');
INSERT INTO  DAN_GR4 (ID,STATUS,TERM,ENROL_DTE,TERM_START_DTE,TERM_END_DATE,UNIT) VALUES ('3',    'DROP'    ,'4',    '15-DEC-13'    ,'25-NOV-13' ,'16-DEC-13',    'LIN');
INSERT INTO  DAN_GR4 (ID,STATUS,TERM,ENROL_DTE,TERM_START_DTE,TERM_END_DATE,UNIT) VALUES ('3',    'DROP'    ,'4',    '15-DEC-13'    ,'25-NOV-13' ,'16-DEC-13',    'POL');
INSERT INTO  DAN_GR4 (ID,STATUS,TERM,ENROL_DTE,TERM_START_DTE,TERM_END_DATE,UNIT) VALUES ('3',    'DROP'    ,'1',    '15-DEC-13'    ,'25-FEB-13' ,'18-MAR-13',    'KIS');
{code}
GIVES:
ID
STATUS
TERM
ENROL_DTE
TERM_START_DTE
TERM_END_DATE
UNIT
1
ENROL
1
15-Mar-13
25-Feb-13
18-Mar-13
KIS
1
DROP
2
27-May-13
27-May-13
17-Jun-13
POL
1
DROP
2
27-Jun-13
27-May-13
17-Jun-13
LIN
1
DROP
3
27-Jun-13
27-May-13
17-Jun-13
PUI
2
DROP
3
26-Sep-13
26-Aug-13
16-Sep-13
POL
2
ENROL
4
26-Nov-13
25-Nov-13
16-Dec-13
LIN
3
DROP
4
15-Dec-13
25-Nov-13
16-Dec-13
LIN
3
DROP
4
15-Dec-13
25-Nov-13
16-Dec-13
POL
3
DROP
1
15-Dec-13
25-Feb-13
18-Mar-13
KIS
WANT:
UNIT
TERM_START_DTE
DROP_BEFORE_END_DATE
TERM
KIS
1
1
1
POL
1
2
POL
1
3
POL
1
4
LIN
1
1
4
LIN
1
2
PUI
1
3
USING:
Oracle Database 10g Enterprise Edition Release 10.2.0.5.0 - 64bi

Answer 1

with
dan_gr4 as
(select '1' id,
        'ENROL' status,
        '1' term,
        to_date('15-Mar-13','dd-MON-rr') enrol_dte,
        to_date('25-Feb-13','dd-MON-rr') term_start_dte,
        to_date('18-Mar-13','dd-MON-rr') term_end_dte,
        'KIS' unit
   from dual
union all
select '1','DROP','2',to_date('27-MAY-13','dd-MON-rr'),to_date('27-MAY-13','dd-MON-rr'),to_date('17-JUN-13','dd-MON-rr'),'POL' from dual union all
select '1','DROP','2',to_date('27-JUN-13','dd-MON-rr'),to_date('27-MAY-13','dd-MON-rr'),to_date('17-JUN-13','dd-MON-rr'),'LIN' from dual union all
select '1','DROP','3',to_date('27-JUN-13','dd-MON-rr'),to_date('27-MAY-13','dd-MON-rr'),to_date('17-JUN-13','dd-MON-rr'),'PUI' from dual union all
select '2','DROP','3',to_date('26-SEP-13','dd-MON-rr'),to_date('26-AUG-13','dd-MON-rr'),to_date('16-SEP-13','dd-MON-rr'),'POL' from dual union all
select '2','ENROL','4',to_date('26-NOV-13','dd-MON-rr'),to_date('25-NOV-13','dd-MON-rr'),to_date('16-DEC-13','dd-MON-rr'),'LIN' from dual union all
select '3','DROP','4',to_date('15-DEC-13','dd-MON-rr'),to_date('25-NOV-13','dd-MON-rr'),to_date('16-DEC-13','dd-MON-rr'),'LIN' from dual union all
select '3','DROP','4',to_date('15-DEC-13','dd-MON-rr'),to_date('25-NOV-13','dd-MON-rr'),to_date('16-DEC-13','dd-MON-rr'),'POL' from dual union all
select '3','DROP','1',to_date('15-DEC-13','dd-MON-rr'),to_date('25-FEB-13','dd-MON-rr'),to_date('18-MAR-13','dd-MON-rr'),'KIS' from dual
select unit,term,max(decode(enrolled,'within','Late')) late_enrolment,max(dropped) when_dropped
  from (select unit,term,
               case when status = 'ENROL'
                    then case when enrol_dte between term_start_dte and term_end_dte
                              then 'within'
                              else 'outside'
                         end
               end enrolled,
               case when status = 'DROP'
                    then case when enrol_dte < term_start_dte
                              then 'before start'
                              when enrol_dte < term_end_dte
                              then 'before end'
                              else 'after end'
                         end
               end dropped
          from dan_gr4
group by unit,term
order by unit,term
UNIT
TERM
LATE_ENROLMENT
WHEN_DROPPED
KIS
1
Late
after end
LIN
2
after end
LIN
4
Late
before end
POL
2
before end
POL
3
after end
POL
4
before end
PUI
3
after end
Regards
Etbin