mysql_stmt_affected_rows

When using UPDATE, MariaDB will not update columns where the new value is the same as the old value. This creates the possibility that mysql_stmt_affected_rows() may not equal the number of rows matched, only the number of rows that were literally affected by the query.

The statement first deletes the record with the same primary key and then inserts the new record. This function returns the number of deleted records in addition to the number of inserted records.