PHP - how to use array in function?

Question

I get an array of values returned from the following function:

function get_subscribitions($user)
{

$user = mysql_real_escape_string ($user);
$sql = "SELECT 'user_id' FROM `subscribe` WHERE subscriber = '$user'";
$result = mysql_query($sql);
$rows = array();   
while ($row = mysql_fetch_assoc($result)) {
   $rows[] = $row;
}    
mysql_free_result($result); 
return $rows;

I now want to use these values in a new function, where each "user_id" is used to collect text from the database through this function:

function get_text($writer) {
$writer = mysql_real_escape_string ($writer);
$sql = "SELECT * FROM `text` WHERE user_id='$writer' ORDER BY timestamp desc";
$result = mysql_query($sql);
$rows = array();
while ($row = mysql_fetch_assoc($result)) {
   $rows[] = $row;
}

mysql_free_result($result);
return $rows;

However the returned value from the first function is an array, and as I've learnt the hard way, arrays cannot be treated by "mysql_real_escape_string".

How can I make the second function handle the values that I got from the first function?

Any responses appreciated. Thank you in advance.

get_text is supposed to work with one user id at a time. Therefore, loop over the array and call get_text once for each item. — Jon
– Jon, Commented Oct 21, 2011 at 13:14
@Jon Would you mind giving me an example on how that loop could be made up? — NorS
– NorS, Commented Oct 21, 2011 at 13:17

dwalldorf · Accepted Answer · 2011-10-21 13:59:44Z

2

Your first mistake is to use mysql_fetch_assoc when only selecting one column. You should use mysql_fetch_row for this. This is likely going to fix your primary problem.

Could look like this:

$subs = get_subscribitions($whateverId);
$texts = get_text($subs);

function get_subscribitions($user)
{
    $user = mysql_real_escape_string ($user);
    $sql = "SELECT 'user_id' FROM `subscribe` WHERE subscriber = '$user'";
    $result = mysql_query($sql);
    $rows = array();

    while ($row = mysql_fetch_row($result)) {
        $user_id = $row['user_id'];
        $rows[$user_id] = $user_id;
    }
    mysql_free_result($result);
    return $rows;
}

function get_text($writer) {
    $writers = implode(",", $writer);
    $sql = "SELECT * FROM `text` WHERE user_id IN ({$writers}) ORDER BY timestamp DESC";
    $result = mysql_query($sql);
    $rows = array();

    while ($row = mysql_fetch_array($result)) {
        $rows[] = $row;
    }

    mysql_free_result($result);
    return $rows;
}

This will save you a lot of time, because you can get all data from 'text' in one statement.

edited Oct 21, 2011 at 13:59

answered Oct 21, 2011 at 13:18

dwalldorf

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4 Comments

dwalldorf Over a year ago

Where is that line in my example?

dwalldorf Over a year ago

anyways, there was something wrong in the code suggested. Should work now.

Markus Hedlund Over a year ago

This is the best solution imo. But you must escape in-data in a query. Change $writers = implode(",", $writer); to $writers = implode(",", array_map('mysql_real_escape_string', $writer)); and you are all set.

dwalldorf Over a year ago

Actually you're right but not really in this case. The data comes directly from the database and can not be manipulated before it is sent to the database again. So I can't see a need to escape it. What you could do is foreach ($writer as $key => $temp) { $writer[$key] = (int) $temp; } before you do $writers = implode(",", $writer); to make sure $writer only holds integer values.

George Cummins · Accepted Answer · 2011-10-21 13:14:29Z

2

The solution is to avoid placing arrays in your $rows array in the first function. Instead of:

while ($row = mysql_fetch_assoc($result)) {
    $rows[] = $row;
}

try:

while ($row = mysql_fetch_assoc($result)) {
    $rows[] = $row['user_id'];
}

This will place only the value from column 'user_id' in the $rows array.

answered Oct 21, 2011 at 13:14

George Cummins

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Comments

Venelin Gornishki · Accepted Answer · 2011-10-21 13:21:11Z

1

In order to use the second function you must iterate over the array returned from the first one. Something like this could work for you:

$user_subscriptions = get_subscribitions($user);
foreach($user_subscriptions as $subscription) {
    $texts = get_text($subscription['user_id']);

    foreach($texts as $text) {
        // do something with the fetched text
    }
}

answered Oct 21, 2011 at 13:21

Venelin Gornishki

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Comments

DaveyBoy · Accepted Answer · 2011-10-21 13:24:04Z

1

As George Cummins says,

while ($row = mysql_fetch_assoc($result)) {
    $rows[] = $row['user_id'];
}

and, to speed up the second function:

function get_text($writer)
{
    $sql = "SELECT * FROM `text` WHERE user_id in (".implode(',',$writer).") ORDER BY timestamp desc";
    $rows = array();
    if ($result = mysql_query($sql))
    {
        while ($row = mysql_fetch_assoc($result))
        {
            $rows[] = $row;
        }

        mysql_free_result($result);
    }    

    return $rows;
}

The change to the query means that you only do one in total rather than one for each ID thus removing the time taken to send the query to the server and get a response multiple times. Also, if the query fails, the function returns an empty array

answered Oct 21, 2011 at 13:24

DaveyBoy

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1 Comment

Markus Hedlund Over a year ago

This is the best solution imo. But you must escape in-data in a query. Change $writers = implode(",", $writer); to $writers = implode(",", array_map('mysql_real_escape_string', $writer)); and you are all set.

gregory · Accepted Answer · 2011-10-21 13:17:12Z

0

Use :

string implode ( string $glue , array $pieces )
// example, elements separated by a comma :
$arrayasstring = impode(",", $myarray);

answered Oct 21, 2011 at 13:17

gregory

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Comments

shox · Accepted Answer · 2011-10-21 13:24:23Z

0

function get_subscribitions($user)
{
  $user = mysql_real_escape_string ($user);
  $sql = "SELECT 'user_id' FROM `subscribe` WHERE subscriber = '$user'";
  $result = mysql_query($sql);
  $row = mysql_fetch_row($results);
  mysql_free_result($result);
  return intval($row['user_id']);
}

it return only the user id you can used it in the 2nd function

answered Oct 21, 2011 at 13:24

shox

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