Difference between Primary and Unique key

If both Primary and Unique key garantees the uniquness of the rows in a table, is there is reason to choose one over the other when creating a table?

Primary Key = Uniqe key + NOT NULL values in the columns.

So u can guess why we need a primary key

Thanks,
Madhu

Unique key does not provide NOT NULL, primary key provide uniquness and NOT NULL

A primary key has to be unique.
A unique key does not have to be a primary key.

How many ways can YOU skin a cat?

MH

Thanks a lot.

Jason