xxxxxxxxxx
select
src.*,
src.start_date - src.prev_end_date gap_days
from (
select
out_tab.emp_no,
(select max(in_tab.end_date) from ABC in_tab where in_tab.emp_no = out_tab.emp_no and in_tab.end_date < out_tab.start_date) prev_end_date,
out_tab.start_date
from
ABC out_tab
) src
where
start_date - prev_end_date > 1;
EMP_NO PREV_END_DATE START_DATE GAP_DAYS
---------- ------------- ---------- ----------
1 29-AUG-10 20-OCT-10 52
3 21-MAR-10 29-MAR-10 8