如何使用php在mysql中生成下一个自动增量数？

Question

I was trying to fetch next auto increment number in mysql using php. I tried this way:

<?
$q=mysql_query("SELECT * FROM `users`");
$next_auto_inc=mysql_num_rows($q)+1;
?>

But, this when any row is deleted don't work. I hope you got what I mean. How can I do this using php?

Answer 1

You can't do that fetching the table data. You have to fetch the table status to get the auto increment number using php. And that, you can do something like this:

$q = mysql_query("SHOW TABLE STATUS LIKE 'test'");
$row = mysql_fetch_assoc($q);
$next_increment = $row['Auto_increment'];
echo "next increment number: [$next_increment]";

Hope this helps :)

[ Source ]

Answer 2

Assuming that you have user_id column as primary key you can also try this:

$q = mysql_query('SELECT MAX(user_id) as user_id from `users`');
$row = mysql_fetch_assoc($q);
$next_auto_inc = $row['user_id'] + 1;