SQL Joining transactions on Date Range - sql

Question

In SQL Server 2014, I'm working with two tables, an EMPLOYEE and a SALES table:
EMPID EMPNAME HIRE_DATE
---------------------------
1234 JOHN SMITH 2021-05-01
1235 JANE DOE 2021-08-05
1236 JANE SMITH 2021-07-31
EMPID SALE_DATE PRODUCT
-------------------------------------
1234 2021-05-05 VPN
1234 2021-05-10 VPN Basic
1234 2021-07-15 Cloud Storage Bronze
1234 2021-07-05 Cloud Storage Gold
1235 2021-10-01 Antivirus
I need to write a query that will produce all rows/columns from the EMPLOYEE table, with a column showing their (aggregated) sales, but ONLY sales that were triggered within 30 days of the hire date.
This query works, but will pull in ALL sales completed until present:
SELECT EMP.*, SALES_30_DAYS
FROM EMP
LEFT JOIN
(SELECT EMPID, COUNT(*)
FROM SALES_30_DAYS
GROUP BY EMPID) ON EMP.EMPID = SALES.EMPID
In this other attempt, HIRE_DATE is not recognized in the sub-query.
SELECT EMP.*, SALES_30_DAYS
FROM EMP
LEFT JOIN
(SELECT EMPID, COUNT(*) SALES_30_DAYS
FROM SALES
WHERE DATEDIFF(DD, HIRE_DATE, SALE_DATE) < 30
GROUP BY EMPID) ON EMP.EMPID= SALES.EMPID
How can I re-write this query, so that the second table will provide the aggregated sales ONLY if the sale took place up to 30 days after the hire date?
Desired outcome:
EMPID EMPNAME HIRE_DATE SALES_30_DAYS
-----------------------------------------
1234 JOHN SMITH 2021-05-01 2
1235 JANE DOE 2021-08-05 1
1236 JANE SMITH 2021-07-31 NULL

Answer 1

WITH EMPLOYEES(EMPID, EMPNAME, HIRE_DATE)AS
(
SELECT 1234, 'JOHN SMITH', '2021-05-01' UNION ALL
SELECT 1235, 'JANE DOE' , '2021-08-05' UNION ALL
SELECT 1236, 'JANE SMITH' ,'2021-07-31'
),
SALES(EMPID, SALE_DATE, PRODUCT) AS
(
SELECT 1234, '2021-05-05' ,'VPN' UNION ALL
SELECT 1234 , '2021-05-10' ,'VPN Basic' UNION ALL
SELECT 1234 , '2021-07-15' ,'Cloud Storage Bronze' UNION ALL
SELECT 1234 , '2021-07-05' ,'Cloud Storage Gold' UNION ALL
SELECT 1235 , '2021-10-01', 'Antivirus'
)
SELECT E.EMPID,E.EMPNAME,E.HIRE_DATE,SALE_QUERY.CNTT
FROM EMPLOYEES E
OUTER APPLY
(
SELECT COUNT(*)CNTT
FROM SALES AS S WHERE E.EMPID=S.EMPID AND
S.SALE_DATE BETWEEN E.HIRE_DATE AND DATEADD(DD,30,E.HIRE_DATE)
)SALE_QUERY
Could you please try if the above is suitable for you