|
|
Posted by Pedro Graca on 01/14/06 02:17
Rich wrote:
<snip>
> $sql = "SELECT DISTINCT name FROM grades order by name";
> $result = mysql_query($sql);
1 query
> if (!$result || mysql_num_rows($result) == 0) { echo mysql_error(); exit; }
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
nice construct!
> $grades = array();
> while ($row = mysql_fetch_row($result)) {
> $grades[$row[0]] = array();
> }
> mysql_free_result($result);
>
> foreach (array_keys($grades) as $name) {
> $sql = "SELECT class, grade FROM grades where name=\"$name\"";
> $result = mysql_query($sql);
a whole bunch of queries!!!
Don't do this if possible.
Avoid doing queries inside loops.
If your table has 1000 names you'd do 1001 queries (one for the
DISTINCT names and 1000 for the classes)
> if (!$result) { echo mysql_error(); exit; }
> while ($row = mysql_fetch_assoc($result)) {
> $grades[$name][$row['class']] = $row['grade'];
> }
> }
> mysql_free_result($result);
Why isn't this inside the foreach loop too?
> print_r($grades);
> ?>
>
> prints:
> Array (
> [jill] => Array ( [chem] => b [psych] => a )
> [joe] => Array ( [bio] => a )
> [john] => Array ( [psych] => b [chem] => a )
> )
Yes, it gets the desired results, but at a *very large* cost!
<snip>
--
Mail to my "From:" address is readable by all at http://www.dodgeit.com/
== ** ## !! ------------------------------------------------ !! ## ** ==
TEXT-ONLY mail to the whole "Reply-To:" address ("My Name" <my@address>)
may bypass my spam filter. If it does, I may reply from another address!
Navigation:
[Reply to this message]
|