Get the number of affected rows by the last INSERT, UPDATE, REPLACE or DELETE query associated with link_identifier.
The MySQL connection. If the link identifier is not specified, the last link opened by mysql_connect is assumed. If no such link is found, it will try to create one as if mysql_connect had been called with no arguments. If no connection is found or established, an E_WARNING level error is generated.
Returns the number of affected rows on success, and -1 if the last query failed.
If the last query was a DELETE query with no WHERE clause, all of the records will have been deleted from the table but this function will return zero with MySQL versions prior to 4.1.2.
When using UPDATE, MySQL will not update columns where the new value is the same as the old value. This creates the possibility that mysql_affected_rows may not actually equal the number of rows matched, only the number of rows that were literally affected by the query.
The REPLACE statement first deletes the record with the same primary key and then inserts the new record. This function returns the number of deleted records plus the number of inserted records.
In the case of "INSERT ... ON DUPLICATE KEY UPDATE" queries, the return value will be 1 if an insert was performed, or 2 for an update of an existing row.
If you are using transactions, you need to call mysql_affected_rows after your INSERT, UPDATE, or DELETE query, not after the COMMIT.
To retrieve the number of rows returned by a SELECT, it is possible to use mysql_num_rows.
Note:Cascaded Foreign Keys
mysql_affected_rows does not count rows affected implicitly through the use of ON DELETE CASCADE and/or ON UPDATE CASCADE in foreign key constraints.