如何在SQL中计算几天到几个月？

Question

I want to calculate days to month like below

Like this:

I am using this code to get months:

DECLARE @Date datetime = '2017-12-06'

SELECT
    CAST(DATEDIFF(M, @Date, GETDATE()) AS varchar) + ' Months and ' + 
        CAST(DATEDIFF(D, @Date, DATEADD(M, - DATEDIFF(M, @Date, GETDATE()), GETDATE())) AS varchar) + ' Days'

Output:

(Result)
3 Months and 4 Days

It works but I need output like this

90 days + 4 days = 94days

Expected output:

Month=3.09041

Thanks in advance

Answer 1

On average, a month has 30.43 days (365.25 / 12). How about just doing this?

SELECT DATEDIFF(days, @Date, GETDATE()) / (365.25 / 12)

This does not produce your exact results but it is a very good estimate of decimal months.