Question

I know you can execute 10 SQL queries inside a mysql_query() (or mysqli_…) but how is that different from executing 10 mysql_query()s with one SQL query in each one?

If they are different and the first solution was more efficient, how would I use mysql_fetch_assoc() function on one of the queries inside of it?

If the first solution allows me to limit the number of connections per page to 1 per mysql_query(), then I think I will have enough mysql connections to handle my traffic, but if it doesn’t, what SQL technology (or other?) can I use that will allow me to connect to my database from PHP more efficiently (so I can handle more users)?

I am using Apache and PHP 5.4

Answer 1

You can only send a single query at a time … see the docs

mysql_query() sends a unique query (multiple queries are not supported) to the currently active database on the server that’s associated with the specified link_identifier.

You could use mysqli_mutli_query .. example from the docs :

$query  = "SELECT CURRENT_USER();";
$query .= "SELECT Name FROM City ORDER BY ID LIMIT 20, 5";

/* execute multi query */
if ($mysqli->multi_query($query)) {
    do {
        /* store first result set */
        if ($result = $mysqli->store_result()) {
            while ($row = $result->fetch_row()) {
                printf("%s\n", $row[0]);
            }
            $result->free();
        }
        /* print divider */
        if ($mysqli->more_results()) {
            printf("-----------------\n");
        }
    } while ($mysqli->next_result());
}

/* close connection */
$mysqli->close();