Splitting out a cost dynamically across weeks - sql

Question

I’m creating an interim table in SQL Server for use with PowerBI to query financial data.
I have a finance transactions table tblfinance with
CREATE TABLE TBLFinance
(ID int,
Value float,
EntryDate date,
ClientName varchar (250)
)
INSERT INTO TBLFinance(ID ,Value ,EntryDate ,ClientName)
VALUES(1,'1783.26','2018-10-31 00:00:00.000','Alpha')
, (2,'675.3','2018-11-30 00:00:00.000','Alpha')
, (3,'243.6','2018-12-31 00:00:00.000','Alpha')
, (4,'8.17','2019-01-31 00:00:00.000','Alpha')
, (5,'257.23','2019-01-31 00:00:00.000','Alpha')
, (6,'28','2019-02-28 00:00:00.000','Alpha')
, (7,'1470.61','2019-03-31 00:00:00.000','Bravo')
, (8,'1062.86','2019-04-30 00:00:00.000','Bravo')
, (9,'886.65','2019-05-31 00:00:00.000','Bravo')
, (10,'153.31','2019-05-31 00:00:00.000','Bravo')
, (11,'150.24','2019-06-30 00:00:00.000','Bravo')
, (12,'690.14','2019-07-31 00:00:00.000','Charlie')
, (13,'21.67','2019-08-31 00:00:00.000','Charlie')
, (14,'339.29','2018-10-31 00:00:00.000','Charlie')
, (15,'807.96','2018-11-30 00:00:00.000','Delta')
, (16,'48.94','2018-12-31 00:00:00.000','Delta')
I’m calculating transaction values that fall within a week. My week ends on a Sunday, so I have the following query:
INSERT INTO tblAnalysis
(WeekTotal
, WeekEnd
, Client
)
SELECT SUM (VALUE) AS WeekTotal
, dateadd (day, case when datepart (WEEKDAY, EntryDate) = 1 then 0 else 8 - datepart (WEEKDAY, EntryDate) end, EntryDate) AS WeekEnd
, ClientName as Client
FROM dbo.tblFinance
GROUP BY dateadd (day, case when datepart (WEEKDAY, EntryDate) = 1 then 0 else 8 - datepart (WEEKDAY, EntryDate) end, EntryDate), CLIENTNAME
I’ve now been informed that some of the costs incurred within a given week maybe monthly, and therefore need to be split into 4 weeks, or annually, so split into 52 weeks. I will write a case statement to update the costs based on ClientName, so assume there is an additional field called ‘Payfrequency’.
I want to avoid having to pull the values affected into a temp table, and effectively write this – because there’ll be different sums applied depending on frequency.
SELECT *
INTO #MonthlyCosts
FROM
(
SELECT
client
, VALUE / 4 AS VALUE
, WEEKENDING
FROM tblAnalysis
UNION
SELECT
client
, nt_acnt
, VALUE / 4 AS VALUE
, DATEADD(WEEK,1,WEEKENDING) AS WEEKENDING
FROM tblAnalysis
UNION
SELECT
client
, VALUE / 4 AS VALUE
, DATEADD(WEEK,2,WEEKENDING) AS WEEKENDING
FROM tblAnalysis
UNION
SELECT
client
, VALUE / 4 AS VALUE
, DATEADD(WEEK,3,WEEKENDING) AS WEEKENDING
FROM tblAnalysis
) AS A
I know I need a stored procedure to hold variables so the calculations can be carried out dynamically, but have no idea where to start.

Answer 1

You can use recursive CTEs to split the data:
with cte as (
select ID, Value, EntryDate, ClientName, payfrequency, 1 as n
from TBLFinance f
union all
select ID, Value, EntryDate, ClientName, payfrequency, n + 1
from cte
where n < payfrequency
)
select *
from cte;
Note that by default this is limited to 100 recursion steps. You can add option (maxrecursion 0) for unlimited numbers of days.

Answer 2

The best solution would be to make use of a numbers table. If you can create a table on your server with one column holding a sequence of integer numbers.
You can then use it like this for your weekly values:
SELECT
client
, VALUE / 52 AS VALUE
, DATEADD(WEEK,N.Number,WEEKENDING) AS WEEKENDING
FROM tblAnalysis AS A
CROSS JOIN tblNumbers AS N
WHERE NCHAR.Number <=52