This is a solution suggested by the MySQl manual:
If expr is given as an argument to LAST_INSERT_ID(), the value of the
argument is returned by the function and is remembered as the next
value to be returned by LAST_INSERT_ID(). This can be used to simulate
sequences:Create a table to hold the sequence counter and initialize it:
mysql> CREATE TABLE sequence (id INT NOT NULL); mysql> INSERT INTO sequence VALUES (0);
Use the table to generate sequence numbers like this:
mysql> UPDATE sequence SET id=LAST_INSERT_ID(id+1); mysql> SELECT LAST_INSERT_ID();
The UPDATE statement increments the sequence counter and causes the next call to LAST_INSERT_ID() to return the updated value. The
SELECT statement retrieves that value. The mysql_insert_id() C API
function can also be used to get the value. See Section 23.8.7.37,
“mysql_insert_id()”.You can generate sequences without calling LAST_INSERT_ID(), but the
utility of using the function this way is that the ID value is
maintained in the server as the last automatically generated value. It
is multi-user safe because multiple clients can issue the UPDATE
statement and get their own sequence value with the SELECT statement
(or mysql_insert_id()), without affecting or being affected by other
clients that generate their own sequence values.