change collation at once

Hi,

i have a large database that has many fields with collation set to latin1_Swedish_ci and i want to change all of them to utf8_unicode_ci at once but i cant find the proper query for that. Something like UPDATE collate SET utf8_unicode_ci WHERE collate=latin1_Swedish_ci;

Is it possible?

Thank you.

On which rdbms?

Sorry, on mysql.