Question

The query returns no results even on the ones where it does work and I am getting the following error.

The datediff function resulted in an overflow. The number of
dateparts separating two date/time instances is too large. Try to use
datediff with a less precise datepart.

But there is nothing to overflow

The following work:

SELECT cis.SaleBK   
FROM dbo.Sales cis
INNER JOIN dim.CalendarDate sd on cis.SaleDateFK = sd.CalendarDatePK
WHERE sd.CalendarDate >= DATEADD(day,-1,dbo.DateToday())

And this one:

SELECT cis.SaleBK
       ,DATEDIFF(s,'1969-01-01',sd.CalendarDate) as SortOrder
FROM dbo.Sales cis
INNER JOIN dim.CalendarDate sd on cis.SaleDateFK = sd.CalendarDatePK
WHERE sd.CalendarDate = DATEADD(day,-1,dbo.DateToday())

But this does not and I can’t figure out why

SELECT cis.SaleBK
       ,DATEDIFF(s,'1969-01-01',sd.CalendarDate) as SortOrder
FROM dbo.Sales cis
INNER JOIN dim.CalendarDate sd on cis.SaleDateFK = sd.CalendarDatePK
WHERE sd.CalendarDate >= DATEADD(day,-1,dbo.DateToday())

Answer 1

I wrote a loop to check when datediff returns an error:

; with  Dates as
        (
        select  cast('2012-01-01' as date) as dt
        union all
        select  dateadd(day, 1, dt)
        from    Dates
        )
select  dt
,       DATEDIFF(s,'1969-01-01',dt)
from    Dates
option  (maxrecursion 0)

The number of seconds since 1969-01-01 and 2037-01-20 is the first that is too large.

So it looks like the maximum number returned by DateDiff is 2^31 or 2147483647.

You can avoid the error by limiting the query’s date range, like:

WHERE  sd.CalendarDate >= DATEADD(day,-1,dbo.DateToday())
       and sd.CalendarDate < '2037-01-20'