Why do I get "Resource id #4" when I apply print_r() to an array in PHP?

Question

Below is the code:

$result=mysql_query("select * from choices where a_id='$taskid'")or die(mysql_error());
print_r($result);

I get "Resource id #4", any idea?

After I added

while($row=mysql_fetch_assoc($result))
{ print_r($row); }

I just got []

What's wrong?

Answer 1

You are trying to print a mysql resource variable instead of the values contained within the resource it references. You must first try to extract the values you have gotten by using a function such as mysql_fetch_assoc().

You might also try mysql_fetch_array() or mysql_fetch_row(), but I find associative arrays quite nice as they allow you to access their values by the field name as in Mike's example. :)

Answer 2

mysql_query() does not return an array as explained in the manual. Use mysql_fetch_array(), mysql_fetch_assoc(), or mysql_fetch_row() with your $result. See the link above for more info on how to manipulate query results.

$result = mysql_query('SELECT * FROM table');
while ($row = mysql_fetch_assoc($result)) {
    echo $row["userid"];
    echo $row["fullname"];
    echo $row["userstatus"];
}

Answer 3

$result is a resource variable returned by mysql_query. More about resource variables: http://php.net/manual/en/language.types.resource.php

You must use other functions such as mysql_fetch_array() or mysql_fetch_assoc() to get the array of the query resultset.

$resultset = array();
$result=mysql_query("select * from choices where a_id='$taskid'") or die(mysql_error());
while($row = mysql_fetch_assoc($result)){
  $resultset[] = $row; // fetch each row...
}
mysql_free_result($result); // optional though...

print_r($resultset);

See:

http://php.net/manual/en/function.mysql-fetch-array.php
http://php.net/manual/en/function.mysql-fetch-assoc.php
http://php.net/manual/en/function.mysql-query.php

Answer 4

Resources are speical variable types used by PHP to track external resources like database connections, file handles, sockets, etc.

http://www.php.net/manual/en/language.types.resource.php