Mysql:Trim all fields in database

Question

UPDATE mytable SET mycolumn= LTRIM(RTRIM(mycolumn));

works fine on trimming columns removing trailer spaces, but how can i adjust it to trim all column

Answer 1

UPDATE mytable SET 
mycolumn = LTRIM(RTRIM(mycolumn)), 
mycolumn2 = LTRIM(RTRIM(mycolumn2)) 

and so on, and so forth.