Question

I want to extract up to five values from an array and place them in a msql query as such:

$frontpage_hot_list_data = array(); 

while (@$row = mysql_fetch_array($sql_frontpage_hot_list)) {
    $frontpage_hot_list_data[] = $row['id']; 
}

$sql_frontpage_hot_down = mysql_query("SELECT * FROM submissions WHERE 
id !='$frontpage_hot_list_data[0]' AND id !='$frontpage_hot_list_data[1]' AND
id !='$frontpage_hot_list_data[2]' AND id !='$frontpage_hot_list_data[3]' AND 
id !='$frontpage_hot_list_data[4]' AND thumbnail_large=0 AND popular=1 AND 
popular_datetime > '$frontpage_hot_hot_three_onlineNowTm' AND 
views > '$frontpage_hot_hot_three_views' ORDER BY views DESC LIMIT 4");

The problem here appears to be when I have less than five values, I get the following error:

Notice: Undefined offset: 1 in
D:\Hosting\8847501\html\scripts\timeframes.php on line 298

Notice: Undefined offset: 2 in
D:\Hosting\8847501\html\scripts\timeframes.php on line 299

Notice: Undefined offset: 3 in
D:\Hosting\8847501\html\scripts\timeframes.php on line 300

Notice: Undefined offset: 4 in
D:\Hosting\8847501\html\scripts\timeframes.php on line 301

Any idea how to solve this problem? Maybe placing in the query only the exact number of variables? Im lost…

Answer 1

You can use implode to create a comma-separated list of your IDs, then put this newly created list into a MySQL IN expression (UPDATE: now I see that you’re using != in your query, so let’s make it NOT IN).

$list = implode(',', $frontpage_hot_list_data);
$sql_frontpage_hot_down = mysql_query("SELECT * FROM submissions WHERE 
id NOT IN ($list) AND thumbnail_large=0 AND popular=1 AND 
popular_datetime > '$frontpage_hot_hot_three_onlineNowTm' AND 
views > '$frontpage_hot_hot_three_views' ORDER BY views DESC LIMIT 4");

Important note: I assumed here that your ids are numeric, so implode() would produce something like 1,5,133,31. If they are strings, then you have to wrap them in apostrophes first using array_map() for example.

Also, if you expect that the array can be empty, you can add another condition that will omit the whole id NOT IN () AND part when necessary.