Running totals with initial value then adding the totals as stated by the date - sql

Question

Imagine we have a table:
SELECT SUM(A) AS TOTALS,DATE,STUFF FROM TABLE WHERE DATE BETWEEN 'DATESTART' AND 'DATEEND'
GROUP BY DATE,STUFF
Normally this gets the totals as:
totals stuff date
23 x 01.01.1900
3 x 02.01.1900
44 x 06.01.1900
But what if we have the previous the data before the startdate,and i want to add those initial data to my startdate value; for example; from the begining of time i already have a sum value of x lets say 100
so i want my table to start from 123 and add the previous data such as:
123
126
126+44 and so on...
totals stuff date
123 x 01.01.1900
126 x 02.01.1900
170 x 06.01.1900
How can i achieve that?
Source data:
WITH Stocks
AS (
SELECT
Dep.Dept_No ,
SUM(DSL.Metre) AS Metre ,
CONVERT(VARCHAR(10), Date, 112) AS Date
FROM
DS (NOLOCK) DSL
JOIN TBL_Depts (NOLOCK) Dep ON Dep.Dept_No = DSL.Dept
WHERE
1 = 1 AND
DSL.Sil = 0 AND
DSL.Depo IN ( 5000, 5001, 5002, 5003, 5004, 5014, 5018, 5021, 5101, 5109, 5303 ) AND
Dep.Dept_No NOT IN ( 6002 ) AND
Dep.Dept_No IN ( 6000, 6001, 6003, 6004, 6005, 6011, 6024, 6030 ) AND
DSL.Date BETWEEN '2013-06-19' AND '2013-06-20'
GROUP BY
Dep.Dept_No ,
CONVERT(VARCHAR(10), Date, 112)
)
SELECT
Stocks.Metre ,
Dep.Dept AS Dept ,
Stocks.Date
FROM
Stocks
LEFT JOIN TBL_Depts (NOLOCK) Dep ON Stocks.Dept = Dep.Dept
ORDER BY
Stocks.Metre DESC

Answer 1

Any RDBMS with window and analytic functions (SQL Server 2012, PostgreSQL but not MySQL)
SELECT
SumA + SUM(SumARange) OVER (ORDER BY aDate ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW) AS TOTALS,
other, aDate
FROM
(
SELECT
SUM(a) AS SumARange,
other, aDate
FROM
SomeTable
WHERE
aDate BETWEEN '20130101' AND '20130106'
GROUP BY
other, aDate
) X
CROSS JOIN
(
SELECT
SUM(a) AS SumA
FROM
SomeTable
WHERE
aDate < '20130101'
) Y
ORDER BY
aDate;
or
SELECT
SUM(SumA) OVER () + SUM(SumARange) OVER (ORDER BY aDate ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW) AS TOTALS,
other, aDate
FROM
(
SELECT
SUM(CASE WHEN aDate < '20130101' THEN a ELSE 0 END) AS SumA,
SUM(CASE WHEN aDate BETWEEN '20130101' AND '20130106' THEN a ELSE 0 END) AS SumARange,
other, aDate
FROM
SomeTable
WHERE
aDate <= '20130106'
GROUP BY
other, aDate
) X
ORDER BY
aDate;
SQLFiddle example and another

Answer 2

Use option with APPLY operator to calculate the totals. You need also add additional CASE expression in the GROUP BY clause
;WITH cte AS
(
SELECT SUM(a) AS sumA, [stuff], MAX([Date]) AS [Date]
FROM SomeTable
WHERE [Date] <= '20130106'
GROUP BY [stuff], CASE WHEN [Date] <= '20130101' THEN 1 ELSE [Date] END
)
SELECT o.total, [stuff], [Date]
FROM cte c CROSS APPLY (
SELECT SUM(c2.sumA) AS total
FROM cte c2
WHERE c.[Date] >= c2.[Date]
) o
See example on SQLFiddle