+6  A: 

No you can't, and it would be a bad idea if you could. Every timestamp in your database is going to use the same space, regardless of how big the number is. (Assuming you are storing the number as a number and not as a string or something.)

Now, if you really want this, you'll have to write it yourself. I.e. subtract the time from your timestamps before putting them into the database, and add the time to the timestamps when you get them back out. But this is asking for maintenance problems. (In fact, using timestamps instead of the database's native DATETIME datatype is asking for problems.)

Kip  2009-09-24 13:49:58
Actually, integers can be compressed using 7-bit encoding, so that values 0 <= x <= (2^7-1) use one byte, (2^7) <= x <= (2^14-1) uses two bytes, etc, which is useful when CPU is cheaper than I/O and you expect most numbers won't be huge.
gustafc  2009-09-24 15:18:39
Which, btw, does not detract from your main point about the wiseness of using the database's DATETIME. But, if you were to do something like this, I'd start by looking for some setting in the database rather than one in the application platform.
gustafc  2009-09-24 15:21:23

related questions

Handling and storing elapsed time
How do I convert local time to UTC in Python?
Mono's DateTime Serialization
Best practices for DateTime serialization in .Net framework 3.5/SQL Server 2008
Parsing exact dates in C# shouldn't force you to create an IFormatProvider
C# Casting vs. Parse
.NET Date Const (with Globalization)
Dynamic regex for date time formats
What is the simplest way to find the difference between 2 times in python?
Best way to convert DateTime to "n Hours Ago" in SQL
What's a good way to overwrite DateTime.Now during testing?
Datetime arithmetic with a string in Ruby
How can I get the DateTime for the Start of the Week?
Is DateTime.Now the best way to measure a function's performance?
SQL Server DateTime conversion failure
Natural language date/time parser for .NET?
What's a good way to check if two datetimes are on the same calendar day in TSQL?
Why does this python date/time conversion seem wrong?
Dealing with PHP server and MySQL server in different time zones
How do I parse and convert DateTime's to the RFC 3339 date-time format?
HOWTO - Compare a date string to datetime in SQL Server?
Best method for varchar date validation in Sybase (T-SQL)?
What's the BEST way to remove the time portion of a datetime value (SQL Server)
How do I calculate relative time?
How do I calculate someone's age in C#?