Set value to NULL in MySQL

Question

I want a value to be set to NULL if nothing is put into the text box in the form I\'m submitting. How can I make this happen? I\'ve tried inserting \'NULL

Answer 1

The answers given here are good but i was still struggling to post NULL and not zero in mysql table.

Finally i noted the problem was in the insert query that i was using

   $quantity= "NULL";
   $itemname = "TEST";

So far so good.

My insert query was bad.

   mysql_query("INSERT INTO products(quantity,itemname) 
   VALUES ('$quantity','$itemname')");

I corrected query to read.

   mysql_query("INSERT INTO products(quantity,itemname) 
   VALUES ('".$quantity."','$itemname')");

So the $quantity is outside of the main string. My sql table now accepted to record null quantity instead of 0