SQL changing a value to upper or lower case

How do you make a field in a sql select statement all upper or lower case?

Example:

select firstname from Person

How do I make firstname always return upper case and likewise always return lower case?

From stackoverflow

• LCASE or UCASE respectively.

  Example:

  SELECT UCASE(MyColumn) AS Upper, LCASE(MyColumn) AS Lower
  FROM MyTable
  

  Joshua Hudson : Is this for mysql?

  Joshua Hudson : UCASE for lower and LCase for Upper?

  Stephen Wrighton : @Joshua - LCASE & UCASE are inherent within the SQL language itself not related to any specific implementation of SQL within a RDBMS. And I fixed the UCASE/LCASE for Lower/Upper thing.

  Joshua Hudson : Thank you. I gave you a up vote because you are right about ISO SQL vs an implementation.

• SQL SERVER 2005:

  print upper('hello');
  print lower('HELLO');
  

  Joshua Hudson : Perfect. Thank you Cirieno! I actually had this answer but wanted it to be documented on stack overflow since I only use this rarely I always forget it. :)

• SELECT UPPER(firstname) FROM Person
  
  SELECT LOWER(firstname) FROM Person
  

  Joshua Hudson : I'm giving Jared the answer since this is closer to my asked question.