Query the differences between records with same ID - ms-access

Question

I have a table like this in MS Access 2019:
+-----------+------------+--------+----------+-------+
| BillingID | Date | RoomID | Electric | Water |
+-----------+------------+--------+----------+-------+
| 1 | 12/23/2018 | 4 | 1669 | 106 |
| 2 | 12/26/2018 | 1 | 5035 | 289 |
| 3 | 12/27/2018 | 6 | 0 | 0 |
| 4 | 12/31/2018 | 5 | 3158 | 223 |
| 5 | 1/6/2019 | 2 | 3823 | 194 |
| 6 | 1/15/2019 | 3 | 1772 | 125 |
| 7 | 1/23/2019 | 4 | 1796 | 117 |
| 8 | 1/26/2019 | 1 | 5231 | 299 |
| 9 | 1/27/2019 | 6 | 0 | 0 |
| 10 | 1/31/2019 | 5 | 3366 | 242 |
| 11 | 2/14/2019 | 2 | 3975 | 201 |
| 12 | 2/15/2019 | 3 | 1839 | 129 |
+-----------+------------+--------+----------+-------+
I could calculate the electricity and water usage with Index & Match in MS Excel. However, I've had a lot of trouble to achieve this with MS Access. The result I want is as below:
+-----------+------------+--------+----------+---------------+-------+------------+
| BillingID | Date | RoomID | Electric | ElectricUsage | Water | WaterUsage |
+-----------+------------+--------+----------+---------------+-------+------------+
| 1 | 12/23/2018 | 4 | 1669 | | 106 | |
| 2 | 12/26/2018 | 1 | 5035 | | 289 | |
| 3 | 12/27/2018 | 6 | 0 | | 0 | |
| 4 | 12/31/2018 | 5 | 3158 | | 223 | |
| 5 | 1/6/2019 | 2 | 3823 | | 194 | |
| 6 | 1/15/2019 | 3 | 1772 | | 125 | |
| 7 | 1/23/2019 | 4 | 1796 | 127 | 117 | 11 |
| 8 | 1/26/2019 | 1 | 5231 | 196 | 299 | 10 |
| 9 | 1/27/2019 | 6 | 0 | | 0 | |
| 10 | 1/31/2019 | 5 | 3366 | 208 | 242 | 19 |
| 11 | 2/14/2019 | 2 | 3975 | 152 | 201 | 7 |
| 12 | 2/15/2019 | 3 | 1839 | 67 | 129 | 4 |
+-----------+------------+--------+----------+---------------+-------+------------+
For example, for RoomID = 4, the ElectricUsage is the difference between the Electric in BillingID #7 and BillingID #1 and so on.
I've tried some answer like this or this but Access ran into errors when using those solutions in SQL view (Syntax error in FROM clause).
Thanks.

Answer 1

You can use a couple of sub-queries to return the Electric/Water for each room on the previous date:
SELECT
B.BillingID, B.BillingDate, B.RoomID, B.Electric,
B.Electric-(SELECT TOP 1 E.Electric FROM tblBilling AS E WHERE B.RoomID=E.RoomID AND E.BillingDate<B.BillingDate ORDER BY E.BillingDate DESC) AS ElectricUsage,
B.Water,
B.Water-(SELECT TOP 1 W.Water FROM tblBilling AS W WHERE B.RoomID=W.RoomID AND W.BillingDate<B.BillingDate ORDER BY W.BillingDate DESC) AS WaterUsage
FROM tblBilling AS B
Note that I've renamed your Date field to be BillingDate, as Date is a reserved word in Access, and will cause you problems in the future.
Regards,