CODEWITHSUNDEEP
mysql
Cory
Cory

Reputation: 742

Inserting NULL into column?

I'm trying to figure out how I can insert a NULL value into a column of newly inserted row.

I'm working on "post icons" which will display a small icon for the thread on the thread list. The icons use RADIO buttons in the form. By default it is set to No Icon. I was wondering what to do for the value of that radio button to make it null? I tried setting value as NULL but it just inserts the word "NULL" into the database.

            $thread_sql = "
            INSERT INTO forum_threads (
                user_id,
                forum_id,
                thread_postdate,
                thread_lastpost,
                thread_title,
                thread_description,
                thread_icon
            ) VALUES (
                '$_SESSION[user_id]',
                '$_GET[f]',
                '$date',
                '$date',
                '$_POST[topictitle]',
                '$_POST[topicdescription]',
                '$_POST[posticon]'
            )
        ";
        $thread_query = @mysqli_query ($db_connect, $thread_sql);

Upvotes: 0

Views: 709

Answers (3)

Pablo Santa Cruz
Pablo Santa Cruz

Reputation: 181270

With MySQL:

insert into your_table (nulled_column) values (null);

If you are getting a 'NULL' literal instead of a null value, it's probably because you are not issuing the right command from your client (PHP, C#, Java program). You will need to share the code you are using for your insertion in order to get more help.

UPDATE:

According to your recently edited question, just get rid of the '' when you are inserting NULL values. If you use '', then you'll get 'NULL' literals inserted as you mentioned.

I would also suggest you use PreparedStatements in MySQL in order to avoid SQL injection attacks.

Upvotes: 4

Cory
Cory

Reputation: 742

This works. Had to use an IF

        if (isset($_POST['submit'])) {
        $thread_sql = "
            INSERT INTO forum_threads (
                user_id,
                forum_id,
                thread_postdate,
                thread_lastpost,
                thread_title,
                thread_description,
                thread_icon
            ) VALUES (
                '$_SESSION[user_id]',
                '$_GET[f]',
                '$date',
                '$date',
                '$_POST[topictitle]',
                '$_POST[topicdescription]',
                IF('$_POST[posticon]'='NULL',NULL,'$_POST[posticon]')
            )
        ";
        $thread_query = @mysqli_query ($db_connect, $thread_sql);

Upvotes: -2

Wrikken
Wrikken

Reputation: 70460

Just do something like this (PDO):

$stmt  = $db->prepare('INSERT INTO foo(bar) values (?);');
$stmt->execute(array($value=='NULL'? NULL,$value));

Or with mysql:

mysql_query('INSERT INTO foo(bar) 
   values ('.($value=='NULL'? 'NULL',"'".mysql_real_escape_string($value)."'").')';

Upvotes: 1

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