UPDATE a column in every row with a random unique number, MySQL

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drop trigger if exists table838654_before_insert;
drop trigger if exists table838654_before_update;
drop table if exists table838654;
create table table838654(
    id int auto_increment primary key,
    random_num int null unique,
    data text
);

insert into table838654 (data) values
    ('data1'),
    ('data2'),
    ('data3'),
    ('data4'),
    ('data5');

select * from table838654;

create trigger table838654_before_update
before update on table838654 for each row 
begin
    declare rnd_num integer;
    loop1: loop
        set rnd_num := FLOOR(RAND() * 10);
        if not exists (select * from table838654 where random_num = rnd_num) then
            set new.random_num = rnd_num;
            leave loop1;
        end if;
    end loop;
end;

update table838654 set random_num = null where 1 = 1;

select * from table838654;

create trigger table838654_before_insert
before insert on table838654 for each row
begin
    declare rnd_num integer;
    loop1: loop
        set rnd_num := FLOOR(RAND() * 10);
        if not exists (select * from table838654 where random_num = rnd_num) then
            set new.random_num = rnd_num;
            leave loop1;
        end if;
    end loop;
end;

insert into table838654 (data) values
    ('data6'),
    ('data7'),
    ('data8'),
    ('data9'),
    ('data10');
    
select * from table838654;


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