Only include employees currently working for company - sql

Question

Thanks to the input I've received earlier on this site, I use the below code to summarize how many months of experience our employees have in a specific market.
The issue however is that the end-result shows the summarized data for all employees, even if they no longer work for our company. What I actually would like, is the same output, but then only for those employees who are still present in the youngest date (SNAPSHOT_DATE).
I managed to get to a solution where I manually update the snapshot every month, but I'd rather go for an automated solution where the code itself determines what the youngest snapshot is.
Many thanks for your support :)
SELECT EMPLOYEE_ID,
ISNULL([Developing & Emerging],0) AS [Experience - D&E],
ISNULL([Developed],0) AS [Experience - D]
FROM
(
SELECT EMPLOYEE_ID,MARKET_TYPE_DESC,COUNT(SNAPSHOT_DATE) T
FROM [db_name].[AGL_V_HRA_FE_R].[VW_HRA_EMPLOYEE_DETAIL]
WHERE ALLC_SER_NUM = '1'
GROUP BY EMPLOYEE_ID,MARKET_TYPE_DESC
)P
PIVOT(
SUM(T)
FOR MARKET_TYPE_DESC IN ([Developing & Emerging],[Developed])
)PVT

Answer 1

It sounds like you are trying to reduce your query down to only return results where [db_name].[AGL_V_HRA_FE_R].[VW_HRA_EMPLOYEE_DETAIL].SNAPSHOT_DATE == the latest snapshot date.
There are multiple ways you can achieve this, but probably the simplest and most easily readable would be something like the following:
DECLARE #SnapshotDate DATETIME
SELECT #SnapshotDate = MIN(SNAPSHOT_DATE ) FROM [db_name].[AGL_V_HRA_FE_R].[VW_HRA_EMPLOYEE_DETAIL]
And then use a CTE to reduce the included list of employees to only those which have a record which matches this snapshot date, by joining the CTE in your main query:
;WITH CTE AS
(
SELECT EMPLOYEE_ID
FROM [db_name].[AGL_V_HRA_FE_R].[VW_HRA_EMPLOYEE_DETAIL]
WHERE SNAPSHOT_DATE = #SnapshotDate
)
SELECT EMPLOYEE_ID,
ISNULL([Developing & Emerging],0) AS [Experience - D&E],
ISNULL([Developed],0) AS [Experience - D]
FROM
(
SELECT ED.EMPLOYEE_ID,ED.MARKET_TYPE_DESC,COUNT(ED.SNAPSHOT_DATE) T
FROM [db_name].[AGL_V_HRA_FE_R].[VW_HRA_EMPLOYEE_DETAIL] ED
JOIN CTE C ON C.EMPLOYEE_ID = ED.EMPLOYEE_ID
WHERE ED.ALLC_SER_NUM = '1'
GROUP BY ED.EMPLOYEE_ID,ED.MARKET_TYPE_DESC
)P
PIVOT(
SUM(T)
FOR MARKET_TYPE_DESC IN ([Developing & Emerging],[Developed])
)PVT

Answer 2

Thanks, #James S! Much appreciated :)
Perhaps a stupid question, but should I just create one query combining both your inputs? Looking like the one below?
DECLARE #SnapshotDate DATETIME
SELECT #SnapshotDate = MIN(SNAPSHOT_DATE ) FROM [db_name].[AGL_V_HRA_FE_R].[VW_HRA_EMPLOYEE_DETAIL]
WITH CTE AS
(
SELECT EMPLOYEE_ID
FROM [db_name].[AGL_V_HRA_FE_R].[VW_HRA_EMPLOYEE_DETAIL]
WHERE SNAPSHOT_DATE = #SnapshotDate
)
SELECT EMPLOYEE_ID,
ISNULL([Developing & Emerging],0) AS [Experience - D&E],
ISNULL([Developed],0) AS [Experience - D]
FROM
(
SELECT EMPLOYEE_ID,MARKET_TYPE_DESC,COUNT(SNAPSHOT_DATE) T
FROM [db_name].[AGL_V_HRA_FE_R].[VW_HRA_EMPLOYEE_DETAIL] ED
JOIN CTE C ON C.EMPLOYEE_ID = ED.EMPLOYEE_ID
WHERE ALLC_SER_NUM = '1'
AND SNAPSHOT_DATE = #SnapshotDate
GROUP BY EMPLOYEE_ID,MARKET_TYPE_DESC
)P
PIVOT(
SUM(T)
FOR MARKET_TYPE_DESC IN ([Developing & Emerging],[Developed])
)PVT
I tried this, but it seems that doesn't work as it gives the following reply:
Incorrect syntax near 'CTE'. If this is intended to be a common table expression, you need to explicitly terminate the previous statement with a semi-colon.```