Question

SELECT Date_Received, DateAdd(Year, DateDiff(year, Cast('3/01/2010 12:00:00AM' as DateTime) , 
    GetDate())-1, Cast('3/01/2010 12:00:00AM' as DateTime)) as minimum_date
FROM [Volunteers].[dbo].[Applications]
WHERE Date_received >= DateAdd(Year, DateDiff(year, Cast('3/01/2010 12:00:00AM' as DateTime),
GetDate())-1, Cast('3/01/2010 12:00:00AM' as DateTime))

In several subqueries where I need to check that a date is within an acceptable range. I need to avoid using a simple constant as I really don’t want to update it or a config file each new school year.

My current solution is to enter the date into the query and use some complicated DATEADD tricks to get the current year(or previous year) into the date I am using in the comparison. The exact code is above. Is there a cleaner way for me to do this?

Thanks

Edit

The business requirement is to find applications submitted between 3/01 and 7/31.

We are running background checks and it costs us money for each check we do. Identifying applications submitted during this time period helps us determine if we should do a full, partial or no background check. I will also need to check if dates concerning the previous year.

We will be doing this every year and we need to know if they were in the current year. Maintaining the queries each year to update the dates is not something I want to do.

So I am looking for a good technique to keep the year parts of the dates relevant without having to update the query or a config file.

Answer 1

If you need to query by month and year a lot, you should also consider making those properties into persisted, computed fields:

ALTER TABLE dbo.Applications
    ADD DateReceivedMonth AS MONTH(Date_Received) PERSISTED

ALTER TABLE dbo.Applications
    ADD DateReceivedYear AS YEAR(Date_Received) PERSISTED

SQL Server will now extract the MONTH and YEAR part of your Date_Received and place them into two new columns. Those are persisted, e.g. stored along side with your table data. SQL Server will make sure to keep them up to date automatically, e.g. if you change Date_Received, those two new columns will be recomputed (but not on every SELECT).

Now, your queries might be a lot easier:

SELECT (list of fields)
FROM dbo.Applications
WHERE DateReceivedYear = 2010 AND DateReceivedMonth BETWEEN 3 AND 7

Since these are persisted fields, you can even put an index on them to speed up queries against them!