SQL Server 2008 query to find rows containing non-alphanumeric characters in a column

Won’t this do it?

SELECT * FROM TABLE
WHERE COLUMN_NAME LIKE '%[^a-zA-Z0-9]%'

Setup

use tempdb
create table mytable ( mycol varchar(40) NULL)

insert into mytable VALUES ('abcd')
insert into mytable VALUES ('ABCD')
insert into mytable VALUES ('1234')
insert into mytable VALUES ('efg%^&hji')
insert into mytable VALUES (NULL)
insert into mytable VALUES ('')
insert into mytable VALUES ('apostrophe '' in a sentence') 

SELECT * FROM mytable
WHERE mycol LIKE '%[^a-zA-Z0-9]%'

drop table mytable 

Results

mycol
----------------------------------------
efg%^&hji
apostrophe ' in a sentence