HelloHello

I got a little Question about Performance of a Subquerry /Joining another table

INSERT
INTO Original.Person
  (
    PID, Name, Surname, SID
  )
  (
    SELECT ma.PID_new , TBL.Name , ma.Surname, TBL.SID 
    FROM Copy.Person TBL , original.MATabelle MA
    WHERE TBL.PID         = p_PID_old
      AND TBL.PID         = MA.PID_old
  );

This is my SQL, now this thing runs around 1 million times or more.
Now my question is what would be faster?

if I change TBL.SID to (Select new from helptable where old = tbl.sid)
or if I add helptable to the from and do the joining in the where?

greets
Auro