Update all values of a column to lowercase

Question

Lets say I have something like this

uid    tag
1      HeLLo
2      heLLO
3      HELLO
4      hello

How can I update all values in the \"tag\" c

Answer 1

Version for case-insensitive matching and including a "WHERE" clause if you don't want to update the entire column:

UPDATE table 
SET tag = LOWER(tag)
WHERE LOWER(tag) != tag
COLLATE Latin1_General_CS_AS

The COLLATE line will make it work if your database uses case insensitive matching, as mine does.