SQL: What is better a Bit or a char(1)

Question

Is there any performance difference on retrieving a bit or a char(1) ?

Just for curiosity =]

UPDATE: Suposing i\'m using SQL Server 2008!

Answer 1

As Adam says, it depends on the database implementing the data types properly, but in theory the following holds:

Bit:

Will store 1 or 0 or null. Only takes a Bit to store the value (by definition!). Usually used for true or false, and many programming languages will interpret a bit as a true or false field automatically.

Char[1]:

A char takes 8 bits, or one byte, so its 8 times larger when stored. You can store (pretty much) any character in there. Will probably be interpreted as a string by programming languages. I think Char[1] will always take the full byte, even when empty, unless you use varchar or nvarchar.