SQL - 按日期和年份求和

Question

I'm trying to write a live report. As of now, I am able to sum by month MONTH(DATEADD(MM, -1, GETDATE())) but it's adding all sales in November. I need it to sum based on month and year from current date -1 month.

PS I cannot do a where clause of YEAR(GETDATE()) = 2021 as this needs to be a live report just in case we want to make it run the past 14 months.

Thank you.

SQL

SUM(
CASE
WHEN COALESCE(month(CONVERT(date,CONVERT(varchar(10),salesdwec.shipdate,120),101)), 0) = month(dateadd(mm, -1,getdate())) THEN
  salesdwec.orderquantity
  ELSE 0
END) AS 'PIROIR_MONTH'

Answer 1

If you are working on SQL-Server, then this should work.

SELECT YEAR(salesdwec.shipdate) 'Year',MONTH(salesdwec.shipdate) 'Month',SUM(salesdwec.orderquantity)
FROM salesdwec
WHERE DATEDIFF(MONTH,salesdwec.shipdate,GETDATE()) = 1
GROUP BY YEAR(salesdwec.shipdate) ,MONTH(salesdwec.shipdate)

As Dale K already mentioned, it would have helped if you provided some sample data.

EDIT:

The query will output the Month and Year column along with order quantity. In case you need only order quantity, you can use this one.

SELECT SUM(salesdwec.orderquantity)
FROM salesdwec
WHERE DATEDIFF(MONTH,salesdwec.shipdate,GETDATE()) = 1