mysql_insert_id() returns the ID generated for an AUTO_INCREMENT column by the previous INSERT query using the given link_identifier. If link_identifier isn't specified, the last opened link is assumed.
mysql_insert_id() returns 0 if the previous query does not generate an AUTO_INCREMENT value. If you need to save the value for later, be sure to call mysql_insert_id() immediately after the query that generates the value.
Note: The value of the MySQL SQL function LAST_INSERT_ID() always contains the most recently generated AUTO_INCREMENT value, and is not reset between queries.
| Warning |
mysql_insert_id() converts the return type of the native MySQL C API function mysql_insert_id() to a type of long. If your AUTO_INCREMENT column has a column type of BIGINT, the value returned by mysql_insert_id() will be incorrect. Instead, use the internal MySQL SQL function LAST_INSERT_ID(). |