SQl Update from table of random Names

Question

I Have a table of random names, simply 3 columns(id, firstname, lastname).

I am trying to have SQL update an entire table of names

Answer 1

update
TestNames left join 
(select ID,
floor(1+(rand()*600)) as rndid
from TestNames) as TN on TN.ID=TestNames.id
left join rndnames on TN.rndid=rndnames.id
set TestNames.fname=rndnames.FirstName,TestNames.lname=rndnames.LastName