While循环中有多个While循环？

Question

Total newbie trying to learn... thanks for all the help so far!

UPDATE - updated code below - Thanks Phill

I'm now trying to get the relevant horse information from a table horses which I can join to race_form with the horse_name field. I want to then display the information for each horse in the race below the while($racecard) info. Does this make it a bit clearer?

I thought I could just do another query and then a while loop with mysql_fetch_array below the one I have already and that would display it and then move onto the next race, but that apparently doesn't work...?!

I'm wondering if you can run 2 while loops after each other inside a while loop? I am working on a horse racing formguide - I can display each race list, but underneath I want to display individual horse details on each horse in the race. Anyway if you look at this page you can see what I'm trying to do:

http://tasmanianracing.com/superform/formguide.php?meetingID=21042011LAUN&Submit=View+Form

Problem is, any time I put a second while loop after the race list, it won't show up. I'm trying to run a query to get the horse details from my horse table and then run a while for each horse in the race, but nothing shows up.

I hope this is clear enough ... my snippet of code is below - please let me know if I've missed out something important:

---

echo "<table width='990' border='1' cellspacing='2' cellpadding='2'>";

$racedetails = mysql_query("SELECT * 
    FROM race_info
    WHERE meetingID = ('" . $safemeetingID . "')");

while($row = mysql_fetch_array($racedetails))
{
    echo "<tr><td>Race " . $row['race_number'] . " at " . $row['start_time'] . " " . $row['class'] . " over " . $row['distance'] . "m</td></tr>";

    $racecard = mysql_query("SELECT *
        FROM race_form
        INNER JOIN race_info ON race_form.raceID = race_info.raceID
        WHERE race_form.raceID = ('" . $row['raceID'] . "')");

    while($row = mysql_fetch_array($racecard))
    {
        echo "<tr><td>" . $row['number'] . "</td><td>" . $row['past10'] . "</td><td>" . $row['horse_name'] . "</td></tr>";
    }

    echo "</table><br>";

    echo "<br>I wish I could put in some horse form here...<br>";

    echo "<table width='990' border='1' cellspacing='2' cellpadding='2'>";

}

echo "</table>";

Answer 1

You'll probably need to change the names of some of the $row variables, they may interfere with each other.

For example:

while($row_races = mysql_fetch_array($totalraces)){
while($row_details = mysql_fetch_array($racedetails)){
while($row_card = mysql_fetch_array($racecard)){

Answer 2

I theory you could and in practice you can, but a while in a while in a for in a while seems a little bit over the top...

I'm sure we can help you make it more efficient if you explain what it is you're trying to do.

Answer 3

I think you can get rid of one of your queries:

The first query gets the number of races by selecting a COUNT, This returns one record with the count value.

// This returns one record with the count
$total_races    = "SELECT COUNT(race_number) AS totalraces 
                   FROM race_info WHERE meetingID = ('".$safemeetingID."') ";

Next you iterate over the the same records as the rows returned for the race details are the same as the count.

// This looks to return the record(s) with the race details
$race_details   = "SELECT * FROM race_info 
                    WHERE meetingID = ('" . $safemeetingID . "')";

I think you can just use this to get the desired results: (I agree to rename the $row variable(s) to something descriptive for each while loop)

$racedetails = mysql_query("SELECT *
FROM race_info
WHERE meetingID = ('" . $safemeetingID . "')");

while($details_row = mysql_fetch_array($racedetails))
{
    echo "<tr><td>Race " . $details_row['race_number'] . " at " . $details_row['start_time'] . " " . $details_row['class'] . " over " . $details_row['distance'] . "m</td></tr>";

    $racecard = mysql_query("SELECT *
    FROM race_form
    INNER JOIN race_info ON race_form.raceID = race_info.raceID
    WHERE race_form.raceID = ('" . $details_row['raceID'] . "')");

    while($rc_row = mysql_fetch_array($racecard))
    {
    echo "<tr><td>" . $rc_row['number'] . "</td><td>" . $rc_row['past10'] . "</td><td>" . $rc_row['horse_name'] . "</td></tr>";
    }

    echo "</table><br>";

    echo "Testing<br>Testing<br>I wish I could put in some horse form here...<br>";

    echo "<table width='990' border='1' cellspacing='2' cellpadding='2'>";

}

NOT TESTED/PSEUDO CODE

"SELECT * 
FROM horses AS h, 
INNER JOIN race_info  AS ri ON race_form.raceID = race_info.raceID
WHERE horse_name IN (
    SELECT horse_name
    FROM race_form AS srf
    WHERE h.horse_name = srf.horse_name
)
AND race_form.raceID = ('" . $details_row['raceID'] . "')"

The idea is to join the two queries into one, I know this is not the correct syntax but it might give you an idea on how to go about it.

Or you can do another query while loop for the horse names

$racedetails = mysql_query("SELECT *
FROM race_info
WHERE meetingID = ('" . $safemeetingID . "')");

while($details_row = mysql_fetch_array($racedetails))
{
    echo "<tr><td>Race " . $details_row['race_number'] . " at " . $details_row['start_time'] . " " . $details_row['class'] . " over " . $details_row['distance'] . "m</td></tr>";

    $racecard = mysql_query("SELECT *
    FROM race_form
    INNER JOIN race_info ON race_form.raceID = race_info.raceID
    WHERE race_form.raceID = ('" . $details_row['raceID'] . "')");

    while($rc_row = mysql_fetch_array($racecard))
    {
        echo "<tr><td>" . $rc_row['number'] . "</td><td>" . $rc_row['past10'] . "</td><td>" . $rc_row['horse_name'] . "</td></tr>";

        $horses = mysql_query("SELECT *
        FROM horses
        WHERE horse_name = ('" . $rc_row['horse_name'] . "')");

        while($horse_row = mysql_fetch_array($horses))
        {
            // echo horse details here
        }
    }

    echo "</table><br>";

    echo "Testing<br>Testing<br>I wish I could put in some horse form here...<br>";

    echo "<table width='990' border='1' cellspacing='2' cellpadding='2'>";

}