Help Req SQL QUERY

Question

Hi All,
I need help to get a sql query for included dates
I have this scenario
create table test (names varchar2(100),start_date date,end_date date,exc_flg number);
insert into test values('John',to_date('01-jan-2009','dd-mon-yyyy'),to_date('31-dec-2011','dd-mon-yyyy'),0);
insert into test values('John',to_date('01-jan-2009','dd-mon-yyyy'),to_date('31-dec-2010','dd-mon-yyyy'),1);
insert into test values('Joseph',to_date('01-jan-2009','dd-mon-yyyy'),to_date('31-dec-2011','dd-mon-yyyy'),0);
insert into test values('Jack',to_date('01-jan-2009','dd-mon-yyyy'),to_date('31-dec-2010','dd-mon-yyyy'),0);
In the above case john is included for this duration start_date is '01-jan-2009' and end_date is '31-dec-2011' and is excluded for this duration '01-jan-2009','31-dec-2010'
Now i want to dispay John's incuded duration as ''01-jan-2011','31-dec-2011'
My sql output should be
Names start_date end_date
John 01-jan-2011 31-dec-2011
Joseph 01-jan-2009 31-dec-2011
Jack 01-jan-2009 31-dec-2010
Thanks in Advance

Answer 1

Hi there,
seems like the old "find those time gaps" problem. I tried to solve it in pure SQL, and since it's Monday I didn't want to wrap my mind around the MODEL clause,
therefore my solution looks a bit cluttered - feel free to improve.
create table test (names varchar2(100),start_date date,end_date date,exc_flg number);
INSERT INTO TEST VALUES('John',to_date('01-01-2009','dd-mm-yyyy'),to_date('31-12-2011','dd-mm-yyyy'),0);
INSERT INTO TEST VALUES('John',to_date('01-01-2009','dd-mm-yyyy'),to_date('31-12-2010','dd-mm-yyyy'),1);
INSERT INTO TEST VALUES('John',to_date('01-04-2011','dd-mm-yyyy'),to_date('01-07-2011','dd-mm-yyyy'),1);
INSERT INTO TEST VALUES('Joseph',to_date('01-01-2009','dd-mm-yyyy'),to_date('31-12-2011','dd-mm-yyyy'),0);
INSERT INTO TEST VALUES('Jack',to_date('01-01-2009','dd-mm-yyyy'),to_date('31-12-2010','dd-mm-yyyy'),0);
INSERT INTO TEST VALUES('Joe',to_date('01-01-2009','dd-mm-yyyy'),to_date('31-12-2011','dd-mm-yyyy'),0);
INSERT INTO TEST VALUES('Joe',to_date('01-04-2010','dd-mm-yyyy'),to_date('31-12-2011','dd-mm-yyyy'),0);
INSERT INTO TEST VALUES('Joe',to_date('01-01-2008','dd-mm-yyyy'),to_date('31-12-2009','dd-mm-yyyy'),1);
select * from test;
WITH t AS (SELECT names
                , 's'        flg_date
                , start_date dat
             FROM TEST            
            WHERE exc_flg = 0  
            UNION ALL
           SELECT names
                , 'e'
                , end_date
             FROM TEST
            WHERE exc_flg = 0  
            UNION ALL
           SELECT names
                , 's'
                , end_date + 1
             FROM TEST
            WHERE exc_flg = 1  
            UNION ALL
           SELECT names
                , 'e'
                , start_date - 1
             FROM TEST
            WHERE exc_flg = 1  
   , t2 AS (SELECT t.*
                 , DECODE(LAG(t.flg_date) OVER (PARTITION BY t.names ORDER BY t.dat), flg_date, 0, NULL, 1, 1) grp_date
              FROM t
             WHERE NOT EXISTS (SELECT 1
                                 FROM TEST t2
                                WHERE t2.names = t.names
                                  AND exc_flg  = 1
                                  AND t.dat    BETWEEN t2.start_date AND t2.end_date)
               AND t.dat BETWEEN (SELECT MIN(start_date)
                                    FROM TEST t2                    
                                   WHERE t2.names = t.names
                                     AND exc_flg  = 0)
                             AND (SELECT MAX(end_date)
                                    FROM TEST t2                    
                                   WHERE t2.names = t.names     
                                     AND exc_flg  = 0)
     , t3 AS (SELECT t2.names
                   , t2.flg_date
                   , t2.dat
                   , SUM(grp_date) OVER (PARTITION BY t2.names ORDER BY t2.dat) grp_date
                FROM t2
   , t4 AS (SELECT t3.*
                 , row_number() OVER (PARTITION BY t3.names, t3.grp_date ORDER BY t3.dat)      rn_start_date
                 , row_number() OVER (PARTITION BY t3.names, t3.grp_date ORDER BY t3.dat DESC) rn_end_date    
              FROM t3
SELECT names
     , dat
     , nxt_dat
  FROM (SELECT t4.names
             , dat
             , CASE WHEN t4.flg_date = 's' THEN LEAD(dat) OVER (PARTITION BY t4.names ORDER BY t4.dat) END nxt_dat
          FROM t4
         WHERE (t4.flg_date = 's' AND rn_start_date = 1)
            OR (t4.flg_date = 'e' AND rn_end_date   = 1)
WHERE nxt_dat IS NOT NULL      
ORDER BY names, dat
NAMES                DAT                 NXT_DAT
Jack                 2009.01.01 00:00:00 2010.12.31 00:00:00
Joe                  2010.01.01 00:00:00 2011.12.31 00:00:00
John                 2011.01.01 00:00:00 2011.03.31 00:00:00
John                 2011.07.02 00:00:00 2011.12.31 00:00:00
Joseph               2009.01.01 00:00:00 2011.12.31 00:00:00C.