Get UserID from RosterResource Table - sql

Question

I have 5 tables: Location, Charge, Resource, Roster and SpecialRoster.
CREATE TABLE Location(
LocationID int identity,
StartDate datetime,
DaysInRoster int)
CREATE TABLE Charge(
ChargeID int identity,
TotalAmount money,
ChargeDate datetime,
UserID int)
CREATE TABLE [Resource](
ResourceID int identity,
ResourceName varchar(100))
CREATE TABLE Roster(
RosterDay int,
ResourceID int,
StartDate datetime,
EndDate datetime,
UserID int)
CREATE TABLE SpecialRoster(
RosterDate datetime,
ResourceID int,
UserID int)
I need to construct a report which shows the sum of Charge.TotalAmount on different days, by ResourceID.
Charge only has a UserID, but the rules are fairly simple:
If the date and ResourceID is in SpecialRoster, the UserID is taken from SpecialRoster
If not, the UserID for the Resource and the RosterDay for the date is taken from the Roster current at that time
Basically, I need to map ResourceID, through UserID from Roster or SpecialRoster, to Charge.
The RosterDay is the current day of the roster, and can be calculated from location, where the RosterDay = DateDiff(day, Location.RosterStartDate, GetDate()) % Location.DaysInRoster
that is, the modulus of the difference between the start of the entire roster at that location, with the number of days in a roster period.
I have written a Function to do this:
CREATE FUNCTION dbo.GetRosteredUser
(
#ResourceID int,
#Date datetime,
#LocationID int
)
RETURNS int
AS
BEGIN
DECLARE #UserID int
DECLARE #RosterOffset int
Select #UserID = UserID from SpecialRoster Where ResourceID = #ResourceID and RosterDate = #Date
If #UserID is NOT NULL
return #UserID
else
Select #RosterOffset = DATEDIFF(day, StartDate, #Date) % DaysInRoster
from Location Where LocationID = #LocationID
Select #UserID = UserID from Roster Where ResourceID = #ResourceID and RosterDay = #RosterOffset
and ( #Date between StartDate and EndDate or #Date > StartDate and EndDate is NULL)
return #UserID
END
GO
But the function isn't great as it is slow, and only allows the report to be run for a single day at a time:
Select a.ResourceID, Name, a.UserID, Sum(c.TotalAmount ) as AmountCharged
from Charge c
left outer join (
Select ResourceID, Name,
dbo.GetUserByResourceDate(ResourceID, '1/FEB/2013', 1) as UserID
from [Resource]) a
on c.UserID = a.UserID
Where ChargeDate between '1/FEB/2013' and '2/FEB/2013'
group by a.ResourceID, Name, a.UserID
Is there a better way to do this? A User will want to run this to compare productivity of a resource over a period of time. eg:
Date ResourceID Name UserID TotalAmount
01/FEB/2013 1 Sales1 22 $1024
02/FEB/2013 1 Sales1 11 $1454
03/FEB/2013 1 Sales1 14 $1900
04/FEB/2013 1 Sales1 23 $3045

Answer 1

Perhaps, something like this might be of help:
SELECT
re.ResourceID,
re.ResourceName,
ch.UserID,
AmountCharged = SUM(ch.TotalAmount)
FROM
Location lo
CROSS JOIN Charge ch
CROSS APPLY (
SELECT DATEDIFF(DAY, lo.StartDate, ch.ChargeDate) % lo.DaysInRoster
) x (RosterDay)
INNER JOIN
[Resource] re
LEFT JOIN Roster ro
ON
ro.RosterDay = x.RosterDay
AND ch.ChargeDate BETWEEN ro.StartDate
AND ro.RecourceID = re.ResourceID
LEFT JOIN SpecialRoster sr
ON
sr.RosterDate = ch.ChargeDate
AND sr.RecourceID = re.ResourceID
ON
ch.UserID = ISNULL(sr.UserID, ro.UserID)
GROUP BY
re.ResourceID,
re.ResourceName,
ch.UserID
WHERE
lo.LocationID = #LocationID
AND ch.ChargeDate BETWEEN ...
;
In the above script, it is assumed that all datetime values are in fact only dates.
Also, I was somewhat surprised not to found a connection between Location and any of the other tables specified. If there is one and you simply forgot to mention it, please let me know if you need any help with incorporating the necessary condition(s) into the script.