I have a table which stores the date and time a task starts and ends and based on the number of hours worked payment will be made in the month end.

The task duration differs from 2 hours to 3 days.

The working time of one day is 8 hours.

I need to find the No. of hours worked in a day.

The data stored in my db is like this

```
sno | start_time            |  end_time           |
---------------------------------------------------
1   |06-10-2016 09:30:00    | 06-10-2016 17:00:00 |
2   |12-10-2016 08:00:00    | 15-10-2016 13:00:00 |

```

I need to get the total hours worked which is 36:30 hours and convert it to days as 5 days.

When I run my query I was able to get this output.

```
sno | start_time         |   end_time          |  time_diff         |
--------------------------------------------------------------------
1   |06-10-2016 09:30:00 |  06-10-2016 17:00:00| +00 07:30:00.000000|
2   |12-10-2016 08:00:00 |  15-10-2016 13:00:00| +03 05:00:00.000000|

```

My query:

```
SELECT  DISTINCT sno,  start_time,end_time, 
TO_TIMESTAMP (end_time,'DD-MM-YYYY HH24:MI:SS') - TO_TIMESTAMP (start_time,'DD-MM-YYYY HH24:MI:SS') AS time_diff
FROM employee WHERE  TO_CHAR((start_time),'MM-YYYY')='10-2016' AND emp_no ='18754';

```

My desired output is

```
|Total_no_days|
---------------
|  5          |

```

But I am unaware of how to proceed now.
Some one please help.