20.4.52 Quels sont les résultats à attendre d'une requête

In addition to the result set returned by a query, you can also get the following information:

• mysql_affected_rows() returns the number of rows affected by the last query when doing an INSERT, UPDATE or DELETE. An exception is that if DELETE is used without a WHERE clause, the table is truncated, which is much faster! In this case, mysql_affected_rows() returns zero for the number of records affected.
• mysql_num_rows() returns the number of rows in a result set. With mysql_store_result(), mysql_num_rows() may be called as soon as mysql_store_result() returns. With mysql_use_result(), mysql_num_rows() may be called only after you have fetched all the rows with mysql_fetch_row().
• mysql_insert_id() returns the ID generated by the last query that inserted a row into a table with an AUTO_INCREMENT index. mysql_insert_id().
• Some requêtes(LOAD DATA INFILE ..., INSERT INTO ... SELECT ..., UPDATE) return additional info. The result is returned by mysql_info(). See the description for mysql_info() for the format of the string that it returns. mysql_info() returns a NULL pointer if there is no additional information.