Sum running total in sql

Question

I am trying to insert a running total column into a SQL Server table as part of a stored procedure. I am needing this for a financial database so I am dealing with accounts and departments. For example, let's say I have this data set:

Account |  Dept  |   Date     |   Value  | Running_Total
--------+--------+------------+----------+--------------
 5000   |  40    | 2018-02-01 |     10   |      15
 5000   |  40    | 2018-01-01 |     5    |      5
 4000   |  40    | 2018-02-01 |     10   |      30
 5000   |  30    | 2018-02-01 |     15   |      15
 4000   |  40    | 2017-12-01 |     20   |      20

The Running_Total column provides a historical sum of dates less than or equal to each row's date value. However, the account and dept must match for this to be the case.

I was able to get close by using

SUM(Value) OVER (PARTITION BY Account, Dept, Date) 

but it does not go back and get the previous months...

Any ideas? Thanks!

Answer 1

You are close. You need an order by:

Sum(Value) over (partition by Account, Dept order by Date)