Query to display spent credits from transactional table

Question

I am working with a table that contains credit transactions where I want to display who\'s credits were spent when a sale is made.

In the table:

• Cre

Answer 1

try this:

WITH Credits_added AS (
    SELECT CreditLogId, OccurredOn, credits
    , SUM(credits) OVER (ORDER BY CreditLogId) - credits AS b --before
    , SUM(credits) OVER (ORDER BY CreditLogId) AS a --after
    , GivenByUserCode
    FROM @CreditLogs
    WHERE Credits > 0)
, Credits_spent AS (
    SELECT CreditLogId, OccurredOn, credits
    , SUM(credits) OVER (ORDER BY CreditLogId) * -1 + credits AS b
    , SUM(credits) OVER (ORDER BY CreditLogId) * -1 AS a
    FROM @CreditLogs
    WHERE Credits < 0)
SELECT s.CreditLogId, s.OccurredOn
, CASE WHEN a.a > s.a THEN s.a ELSE a.a END - CASE WHEN a.b > s.b THEN a.b ELSE s.b END AS Credits 
, a.GivenByUserCode
FROM Credits_added AS a
INNER JOIN Credits_spent AS s ON a.a > s.b AND s.a > a.b

Answer 2

since you mentioned there will be 4 to 5 million records per year, even if this can be done by query it will be an slow query.

I would suggest to have another table like creditSpent which contains (PurchaseCreditLogId , additionCreditLogId, Amount)

And in the time of inserting purchases, find all records, calculate the amount that should be reduced from each one and store that information in that table

Then when you are running your report you can do a simple query on this table