sql with group by and range of dates - sql

Question

I have a query which uses max aggregate function to calculate reset date for a particular selection date.There is a table vp_Accrual which have effectivedate field.selection date is passed to effectivedate field and based on that using Max function, reset date is calculated.This Query gives result only for a particular selection date.It calculate a reset date based on selection date passed.
I want to modify it so that it will give me reset date for a range of dates
Below Query gives Output for one person for the date 1st Jan as follow.
We need to modify Query so that it will give result for multiple selection date instead of only one selection date.
I tried by adding addition #enddate field as effectivedate between #selectiondate and #enddate.
But I guess tha approach is not correct.
I want to pass range of date, such as 1st jan to 4th Jan, and it should give Output for each date as below
[Image is added as Link as i dont have enough Repuation Point][https://i.stack.imgur.com/0HSX1.jpg]
Below is the Query used.
DECLARE #selectionDate datetime
SET #selectionDate = CONVERT(nvarchar(10), DATEADD(dd, 0, CAST('01/01/2017' AS datetime)), 101)
SELECT
e.personnum,
ac.name as Accrul_Code,
#selectionDate as Selection_DATE,
CASE
WHEN MAX(va.effectivedate) IS NULL THEN CAST('1/1/1753' AS datetime)
ELSE MAX(va.effectivedate)
END AS resetdate
FROM vp_employeev42 e WITH (NOLOCK)
INNER JOIN accrualprofile ap
ON e.accrualprflname = ap.name
INNER JOIN accrualprofilemm apm
ON apm.accrualprofileid = ap.accrualprofileid
INNER JOIN accrualrule ar
ON apm.accrualruleid = ar.accrualruleid
INNER JOIN accrualcode ac
ON ac.accrualcodeid = ar.accrualcodeid
LEFT OUTER JOIN vp_accrual va
ON va.accrualcodeid = ar.accrualcodeid
AND e.personid = va.personid
AND accrualtrantype IN (3, 11)
AND va.effectivedate <= #selectionDate
WHERE
ac.NAME IN ('FT PTO','LOC','EPT - 5','PT PTO','EPT')
AND va.DISQUALIFIEDSW != 1
and e.PERSONNUM='00152'
GROUP BY e.personnum,
ac.name
Please help me with this Query

Answer 1

Best I can make out, you want a Cartesian join on a fake date table that will cause your results to repeat themselves over and over, but for a different set of dates each time
Something like this:
DECLARE #selectionDate datetime
DECLARE #endDate datetime
SET #selectionDate = DATEFROMPARTS(2017,1,1)
SET #endDate = DATEFROMPARTS(2017,5,1)
WITH dates ( IncDate ) AS (
SELECT #selectionDate UNION ALL
SELECT DATEADD(month,1,IncDate) FROM dates WHERE Incdate <= #endDate )
SELECT
e.personnum,
ac.name as Accrul_Code,
IncDate as Selection_DATE,
MAX(COALESCE(effectivedate, CAST('1/1/1753' AS datetime)) AS resetdate
FROM vp_employeev42 e WITH (NOLOCK)
INNER JOIN accrualprofile ap
ON e.accrualprflname = ap.name
INNER JOIN accrualprofilemm apm
ON apm.accrualprofileid = ap.accrualprofileid
INNER JOIN accrualrule ar
ON apm.accrualruleid = ar.accrualruleid
INNER JOIN accrualcode ac
ON ac.accrualcodeid = ar.accrualcodeid
CROSS JOIN dates
LEFT OUTER JOIN vp_accrual va
ON va.accrualcodeid = ar.accrualcodeid
AND e.personid = va.personid
AND accrualtrantype IN (3, 11)
AND effectivedate <= IncDate
WHERE
ac.NAME IN ('FT PTO','LOC','EPT - 5','PT PTO','EPT')
AND va.DISQUALIFIEDSW != 1
and e.PERSONNUM='00152'
GROUP BY e.personnum,
ac.name,
IncDate
A few cautions though:
This query cannot generate the results you posted, but neither can yours. There's no logic at all to your example results, where your reset date is the max date that is less than the selection date but your first of February selection date somehow chooses the tenth of Jan, yet your first of march selection date chooses the eleventh of Jan.
This is totally untested; you provided no sample data, only an image of the results, and I post from an iPad, so generating test data would be incredibly laborious, typing it all in
You mix up your dates as varchar and datetime. Please be more diligent in keeping these data types separate. Always work with dates as dates, not strings. Never store dates as string. Never rely on implicit conversions between date and string
DATEFROMPARTS came along in sqlserver 2012 I think, if your sql is older than this, use convert with a format string to turn your string into a date.. do not declare selectiondate as a varchar!