Calculating Running Total After Reset

Question

I have a SQL Server 2012 table which has customer id, amount, and a reset columns. I’m trying to calculate the running total and also calculate the running total after reset. Once the reset "flag" is set then I want to calculate the running total after the running total.

I have the following code and not sure if there's a way to calculate running total after a break point.

WITH a
AS
(SELECT
        *
        ,SUM(amount) OVER (ORDER BY id) AS RunningTotal
    FROM Table1)
SELECT
    *
    ,CASE
        WHEN resetYN = 1 THEN 0
        ELSE Amount + LAG(RunningTotal, 1) OVER (ORDER BY id)
    END AS ResetRunningTotal
FROM a

Answer 1

Here's one method of getting running totals after reset. There are probably others out there. Here is your test data:

CREATE TABLE user20907 (
ID INTEGER NULL,
CUSTOMERID INTEGER NULL,
AMOUNT INTEGER NULL,
RESETYN INTEGER NULL
);

BEGIN TRANSACTION;
INSERT INTO user20907 VALUES (1,111,5,0);
INSERT INTO user20907 VALUES (2,111,6,0);
INSERT INTO user20907 VALUES (3,111,7,1);
INSERT INTO user20907 VALUES (4,111,8,0);
INSERT INTO user20907 VALUES (5,111,9,0);
INSERT INTO user20907 VALUES (6,111,4,1);
INSERT INTO user20907 VALUES (7,111,7,0);
INSERT INTO user20907 VALUES (8,111,9,0);
COMMIT TRANSACTION;

First get a running total of the ResetYN column. I'm going to call it SUM_OF_RESETYN. In an outer query you can partition by both CustomerID and SUM_OF_RESETYN. For the reset running total, instead of taking Amount directly you can do a case statement similar to what you already have:

SELECT
      t.ID
    , CUSTOMERID
    , AMOUNT
    , RESETYN
    , RUNNINGTOTAL
    , SUM(CASE WHEN RESETYN = 1 THEN 0 ELSE AMOUNT END) OVER (PARTITION BY CUSTOMERID, SUM_OF_RESETYN ORDER BY ID) RESETRUNNINGTOTAL
FROM
(
    SELECT
          ID
        , CUSTOMERID
        , AMOUNT
        , RESETYN
        , SUM(AMOUNT) OVER (PARTITION BY CUSTOMERID ORDER BY ID) RUNNINGTOTAL
        , SUM(RESETYN) OVER (PARTITION BY CUSTOMERID ORDER BY ID) SUM_OF_RESETYN
    FROM user20907
) t;

I ran that query and the results matched yours, except that I did not have a NULL value for RESETRUNNINGTOTAL for ID 1. Was that intentional? If so it should be easy to integrate that bit of logic into my query.