php mysql query within foreach loop not working

Question

Name pretty much explains it all--

I have an array and I want to run a query for each item in the array

Two variables come from this, volume and page number -- the volumes are contained within the array and I need to pull the respective page numbers for each volume

heres my code:

$volsArr = array(1, 2, 3, 4);

foreach ($volsArr as $volume) {
 $pages = mysql_query("SELECT page FROM $table WHERE vol = '$volume' LIMIT 1");
    if (!$pages) { die("Query to show fields from table failed"); }
      while($row = mysql_fetch_array($pages)) {
       $page = $row['page'];
      }
    echo 'volume is '.$volume.'';
    echo 'page is '.$page.'';
   }

I can't figure out what the issue I'm having is, I am getting an output like this:

Volume is 1 Page is 40

(this is correct for volume 1)

Volume is 2 Page is 40

(page should be 8)

Volume is 3 Page is 40

(page should be different again)

etc...

I tried unset($page) before closing the loop but that doesn't seem to do anything, any help, please!

And I also tried moving the echos so they are inside the while($row...) loop, but that will only provide me with output for the first item in the array....

Based on your update, the reason is: Rows do not exist where vol in ('2','3','4') — Fosco
– Fosco, Commented Jun 3, 2011 at 18:51
Also, due to the "LIMIT 1" in the query, you don't really need the while loop; just use mysql_fetch_assoc ($result) once to get that single row. You can then use mysql_num_rows ($result) to check if the query returned anything. EDIT: Sorry, use mysql_num_rows before fetching. — Martin Vrkljan
– Martin Vrkljan, Commented Jun 3, 2011 at 18:55

Ram Sharma · Accepted Answer · 2015-08-04 15:24:14Z

1

Based on your update, the reason is: Rows do not exist where vol in ('2','3','4')

$page is never being updated because there are no rows to fetch.

edited Aug 4, 2015 at 15:24

Ram Sharma

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answered Jun 3, 2011 at 18:49

Fosco

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3 Comments

Thomas Over a year ago

it seems like this is the issue but its blowing my mind because there is data in the row when i view it via myadmin... EDIT: also the query returns the proper info in myadmin

Thomas Over a year ago

turns out I set my array up improperly and it had nothing to do with the query -- thanks for pointing this out though because I don't think I would have ever figured it out on my own -- it's always right in front of my face...

Fosco Over a year ago

@thomas Try building the query in a string first and echoing that so you can test exactly what the php script is going to execute.

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