Copied part of your question without any changes put in search:

Found one of the possible options.
Another, if you know the maximum number of records, it is possible in one table to start with 0 increment, the other from the highest possible number
Bad Google! Since refuses to help you!
p.s. what for you is? There is something wrong.....
Premature optimization is the root of all evil. - molly.Stanton commented on July 8th 19 at 16:04