Re: mySQL query question

Chris wrote:

Jim Lucas wrote:

mikesd1@verizon.net wrote:

Ok, so just that I am clear, you are SELECTing and pulling all the data that you are submitting in the above INSERT statement from the DB initially, then you are only modifying the confirm_number value and then re- submitting all the values, as they originally were,

Well, actually when all is said and done, a new record will be created with new information (Name, phone, email, etc) and the confirm_number is the previous+1

Seems like a perfect candidate for an auto-inc field, though mysql doesn't let you have multiple in the same table (afaik).

I would agree, but I'm not the OP. He/She wanted it this way...

You do have a race condition, you can end up with 2 of the same confirm_numbers (you'd have to be unlucky, but it can happen). 2 hits at the same time = 2 selects getting the same max(confirm_number), which results in 2 inserts with the same number.

Granted that their is a possibility that it could happen. But the chance of it happening with the three statements running back-to-back in the same call is much lower then having three separate calls and doing the math in PHP. -- Jim Lucas "Some men are born to greatness, some achieve greatness, and some have greatness thrust upon them." Twelfth Night, Act II, Scene V by William Shakespeare