select concat(
case when round((rand())*25) > 12 then char(round((rand())*25)+97) else char(round((rand())*25)+65) end,
case when round((rand())*25) > 12 then char(round((rand())*25)+97) else char(round((rand())*25)+65) end,
case when round((rand())*25) > 12 then char(round((rand())*25)+97) else char(round((rand())*25)+65) end,
case when round((rand())*25) > 12 then char(round((rand())*25)+97) else char(round((rand())*25)+65) end,
case when round((rand())*25) > 12 then char(round((rand())*25)+97) else char(round((rand())*25)+65) end,
case when round((rand())*25) > 12 then char(round((rand())*25)+97) else char(round((rand())*25)+65) end
) as keka;
insert into table1 (a,b)
values(CONCAT('($%)F',keka),'e51d744514b334228d43dd605d556a61');
SET v = v + 1;