Using SQL to get the SUM of X records

Question

I have a SQL Server 2019 stored procedure which will allow a user to enter the number of minutes of calls they want to see. If he enters 20 minutes, then I want to show him the first x number of records where the of sum of call_length = 20 and < 21 (rounded to the nearest minute) of all of the records.

My code below just selects the records where call_length is between 20 and 21. I need the sum of the call_length of the records to be between 20 and 21. Thanks

DECLARE @Call_Mins int
SET @Call_Mins = 20

SELECT
    reviewid, cumulativesum  
FROM
    (SELECT 
         reviewid, 
         SUM(CONVERT(float,REPLACE(Call_Length,':','.'))) OVER (PARTITION BY ReviewID ORDER BY ReviewID ASC) AS cumulativesum
     FROM 
         LegacyReviews) t 
WHERE
    cumulativesum >= @Call_Mins 
    AND cumulativesum <= @Call_Mins + 1

Data looks like this:

Answer 1

This answer is assuming that your [Call_Length] is stored as a Time datatype. (hh:mm:ss) 

DECLARE @Call_Mins AS INT
SET @Call_Mins = 20;

WITH cte as ( 
    SELECT
        [reviewid],
        [Call_Length],
        [RunningTotal] = SUM(DATEDIFF(SECOND, '00:00:00', [Call_Length])) OVER (ORDER BY [reviewid])
    FROM [LegacyReviews])
SELECT
    cte.[reviewid],
    cte.[Call_Length]
FROM cte
WHERE [RunningTotal] < (@Call_Mins + 1) * 60

This query uses a Common Table Expression and a running total, that isn't returned per your question, that will not return anything past the first x number of rows that add up to whatever @Call_Mins is set to (+ 1). This would, in your example, return any values up to 20:59