How depends on what's the exact logic you want to use. Most likely you want to remove all "0" characters on the beginning of each personnel number. One possible implementation is finding the first non-zero character and use the position in subStr().
Be aware of that it could (depending on your data) create duplicate values, which would cause the process to fail. You should check for this problem before actually changing any data (and update the logic if needed).
I'm not sure what you mean by "to say which table records effected". It's done by your code, so you can add any kind of logging you like.