Whenever querying anything with Date and Time as one of the field under <where\> condition
<FieldRef Name=’Created’ /><Value Type=’DateTime’ IncludeTimeValue=’TRUE’/>
Or in another words would it be possible to introduce something like Today – 5 (days ?)
Big Answer after lots of search is YES
If you want to work with the date of today, you could use the syntax <Today /> and if you want to do simple calculations i.e. adding or subtracting a certain number of days of today’s date you could make use of the syntax <Today OffsetDays=”5″ />.
In a content query web part you could integrate a query like the following:
<Value Type=”DateTime”><Today OffsetDays=5 /></Value>
In case of more complex calculations on dates, you could make use of SPUtility.CreateISO8601DateTimeFromSystemDateTime in combination with the different calculation methods on the DateTime data type.
I have seen that some guys uses [Toda-2Day(s)] format to add/substract no if days from date, but it never worked for me.