Question

In WORK_TIME column in my database table (EMP_WORKS), i have records as below.

WORK_TIME

19:03:00
20:00:00
21:02:00
21:54:00
23:04:00
00:02:00

i want to create a database view using these data. for it i need to get Gap between these times as below.

WORK_TIME  GAP

19:03:00  -
20:00:00  00:57:00  (Gap between 19:03:00 and 20:00:00)
21:02:00  01:02:00  (Gap between 20:00:00 and 21:02:00)
21:54:00  00:52:00  (Gap between 21:02:00 and 21:54:00)
23:04:00  01:10:00  (Gap between 21:54:00 and 23:04:00)
00:02:00  00:58:00  (Gap between 23:04:00 and 00:02:00)

How could i do this ?

Answer 1

According to your desired result, provided in the question, you want to see time interval. And also I suppose that the WORK_TIME column is of date datatype and there is a date part(otherwise there will be a negative result of subtraction (previous value of WORK_TIME from 00.02.00)).

SQL> create table Work_times(
  2    work_time
  3  ) as
  4  (
  5  select to_date('01.01.2012 19:03:00', 'dd.mm.yyyy hh24:mi:ss') from dual union all
  6  select to_date('01.01.2012 20:00:00', 'dd.mm.yyyy hh24:mi:ss') from dual union all
  7  select to_date('01.01.2012 21:02:00', 'dd.mm.yyyy hh24:mi:ss') from dual union all
  8  select to_date('01.01.2012 21:54:00', 'dd.mm.yyyy hh24:mi:ss') from dual union all
  9  select to_date('01.01.2012 23:04:00', 'dd.mm.yyyy hh24:mi:ss') from dual union all
 10  select to_date('02.01.2012 00:02:00', 'dd.mm.yyyy hh24:mi:ss') from dual
 11  )
 12  /

Table created

SQL> 
SQL> select to_char(t.work_time, 'hh24.mi.ss') work_time
  2         , (t.work_time -
  3            lag(t.work_time) over(order by WORK_TIME)) day(1) to second(0) Res
  4  from work_times t
  5  ;

WORK_TIME RES
--------- -------------------------------------------------------------------------------
19.03.00  
20.00.00  +0 00:57:00
21.02.00  +0 01:02:00
21.54.00  +0 00:52:00
23.04.00  +0 01:10:00
00.02.00  +0 00:58:00

6 rows selected