Question

Say, if I need to select records from the database where the date field is in a particular time frame. The select query would be this:

SELECT * FROM [MyTable] WHERE [Date] >= @RangeBegin AND [Date] <= @RangeEnd;

But I have a little condition when the Date field might be empty or invalid. In that case the date value should be taken from @DefaultDate.

How do you put all this into SQL?

Answer 1

Since you say that the date can be invalid I assume you have stored dates as varchar.
You can use isdate to check if the date is valid.

select case isdate([Date]) 
         when 1 then cast([Date] as datetime)
         else @DefaultDate 
       end as [Date]
from MyTable
where case isdate([Date]) 
        when 1 then cast([Date] as datetime)
        else @DefaultDate 
      end between @RangeBegin and @RangeEnd