21.8.15.2. What Results You Can Get from a Query

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.

For a fast re-create, use TRUNCATE TABLE.
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. See Section 21.8.7.37, "mysql_insert_id()".
Some queries (LOAD DATA INFILE ..., INSERT INTO ... SELECT ..., UPDATE) return additional information. 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.