I have a table like this
| Order ID | Department | Item | Order Date | EndOrderDate | DiffTime |
|---|---|---|---|---|---|
| 1 | dep1 | it_1_1 | 01-01-2022 | 02-01-2022 | 1 |
| 1 | dep1 | it_1_2 | 01-01-2022 | 02-01-2022 | 1 |
| 2 | dep1 | it_2_1 | 02-01-2022 | 04-01-2022 | 2 |
| 2 | dep1 | it_2_2 | 02-01-2022 | 04-01-2022 | 2 |
| 3 | dep2 | it_3 | 02-01-2022 | 05-01-2022 | 3 |
In my view a need a table with average response time for order
| Department | average time |
|---|---|
| Dep1 | 1.5 |
| Dep1 | 3 |
How can i do it? If i use average i get all the value from all item, but i need to include value only once for order