Denis,

Thanks for the feedback on the RC0 DMVs.

An interesting set of date/time examples!

For your example query:

SELECT CAST('00:15:00' as TIME(0)) + 5

The error message is:

Operand type clash: time is incompatible with int

This refers to data type incompatibilities (time versus int), but does not mention overloaded operator incompatibilities for the + operator (perhaps it stops evaluating for errors after hitting the first error).

I modified the sample query to:

SELECT CAST('00:15:00' as TIME(0)) + CAST('05:00:00' as TIME(0))

to make both operands of the same data type and attempt to add 15 minutes and 5 hours (as in your DateAdd example), and received a different error message:

Operand data type time is invalid for add operator.

This error suggests that the + operator is not overloaded for the new Time(0) data type, despite the fact that the + operator appears to be overloaded for the DateTime data type being returned by GetDate (with the 5 being implicitly interpreted as number of days to add to the current date).

Assuming that CAST('00:15:00' as TIME(0)) + 5 did work, what implicit time unit measure should be applied to the 5 operand?

- Hours

- Minutes

- Seconds

- Days (24 hour periods)

- Something else?

Based on the GetDate() + 1 interpreting the 5 as days, I might guess that the 5 is implicitly interpreted as the lowest whole (non-fractional) time unit, which would be seconds.

I guess that while DateAdd is less straightforward to use, it has the advantage of explicitly choosing the time unit measure and quantity to add (the "hh, 5" being 5 hours).

The .NET framework has a data type called TimeSpan which represents a time interval (an amount of time between two date / time values, in days, hours, minutes, seconds, and fractions of seconds).  If I recall correctly, you can add or subtract a date/time and an internal (TimeSpan), resulting in a DateTime (such as your example of time 0:15:00 and interval 05:00:00 resulting in time 05:15:00).  Or you can subtract two date/time values resulting in an interval value.  But you can't add two date/time values together (incompatible data types).  Unfortunately, there is no equivalent to TimeSpan as a native SQL Server data type (even in SQL 2008).

Scott R.

You can use the gettime() function to do this but you have to put in the cheat code. up up down down left right left right b a