Using Max with CTE and CASE T-SQL - sql-server

Question

I am trying to use MAX() to select the most recent placement date within our database, and use Table_CTE so I can then select and filter between the dates desired.
BEGIN
DECLARE #Rangetill DATE, #Rangefrom DATE
SET #rangefrom = DATEADD(day, -50, GETDATE())
SET #Rangetill = DATEADD(day, -90, GETDATE());
WITH Table_CTE (Name, ID, Rangefrom, Rangetill, StatusID, Statusdate) AS
(
SELECT
PE.Personname + ' ' + PE.Surname [Name],
A.ApplicantId,
#rangefrom [Expiry warning from],
#rangetill [Expiry warning till],
A.Statusid,
selected = CASE
WHEN P.EndDate IS NOT NULL AND P.EndDate > A.StatusDate
THEN CONVERT(DATE, P.EndDate, 103)
ELSE CONVERT(DATE, A.StatusDate, 103)
END
FROM
Applicants AS A
LEFT JOIN
Person AS PE ON A.ApplicantId = PE.PersonID
LEFT JOIN
Placements AS P on A.applicantid = P.Applicantid
)
SELECT *
FROM Table_CTE
WHERE table_cte.Statusdate BETWEEN #Rangetill AND #Rangefrom
AND (Table_CTE.StatusID = 58 OR Table_CTE.statusid = 63)
ORDER BY Name DESC
END
The above selects the right information but also selects duplicate applicants with placement end dates (p.enddate) as they could have been placed more than once. The WHERE clause also limits the most recent enddate to within the range provided by the Variables and as there needs to be a log there will be multiple end dates. so my solution or idea would be to uses a max() within the Case or CTE Select. However I am not sure how to use or work with Max() in this case.
In this case I would like to check and return the Max(p.enddate) if it exists and store that in the statusdate of Table_CTE.
Is this possible and is it the best way to provide this information in a stored procedure?

Answer 1

In the CTE would be more efficient but this is easier
SELECT c.[Name], max(c.Statusdate)
FROM Table_CTE c
WHERE c.Statusdate Between #Rangetill and #Rangefrom
AND c.StatusID in (58, 63)
group by c.[Name]
Add the other columns on your own

Answer 2

Declare
#Rangetill date,
#Rangefrom date
SET #rangefrom = DATEADD(day, -50, GETDATE())
SET #Rangetill = DATEADD(day, -90, GETDATE());
With Table_CTE ( ID, Rangefrom, Rangetill, Statusdate)
AS (
Select
A.ApplicantId
, #rangefrom [Expiry warning from]
, #rangetill [Expiry warning till]
, selected = CASE
WHEN max(P.EndDate) IS NOT NULL AND max(P.EndDate) > max(A.StatusDate)
THEN max(CONVERT(DATE, P.EndDate, 103))
ELSE max(CONVERT(DATE, A.StatusDate, 103))
END
FROM Applicants AS A
LEFT JOIN Person AS PE ON A.ApplicantId = PE.PersonID
LEFT JOIN Placements AS P on A.applicantid = P.Applicantid
GROUP BY A.ApplicantId
)
SELECT
PE.PersonName + ' ' + PE.Surname [NAME]
, A.ApplicantId
, Table_CTE.ID
, Table_CTE.Statusdate
, #Rangefrom [Range from]
, #Rangetill [Range till]
FROM Table_CTE
LEFT JOIN Applicants AS A ON A.ApplicantId = Table_CTE.ID
LEFT JOIN Person as PE on PE.PersonID = A.ApplicantId
WHERE table_cte.Statusdate Between #Rangetill and #Rangefrom
AND (A.StatusID = 58 or A.statusid = 63 )
Order by PE.PersonName + ' '+ PE.Surname desc
END
Really messy way around things but I got my solution by removing all but the variables and ID from CTE so I could select Max(DATE) on both A.statusdate and P.EndDate.
By doing this I could group by A.ApplicantID and rejoin specific tables outside of the CTE in order to get Applicant Name and Status ID back into my results set.
Thank you for your help everyone.