[SOLVED] Simple question about php

[SocomNegotiator]

Ok I have a submit button that takes the values entered and enters them into a database...pretty simple. Well if the quantity is not entered I want nothing to be put into the database under that field. However, it is putting a "0" into the field. I even have this code to try and prevent that...

 

if($amount = ""){
	$amount = "";
}

 

Also I have the structure of this field set to Null. I had it as Not Null before and the default was zero. I thought by changing that to Null would change it, but it did not. Any suggestions?

[flyhoney]

If you use NULL in your query it should work.

 

UPDATE table SET column = NULL WHERE id = 1

[Mchl]

First of all, your code will not work. It will always insert empty value, because you're doing an assignment in if() construct instead of comparison.

That's how it's supposed to be.

if($amount == ""){
      $amount = "";
   }

 

Second thing. How is the field in database defined. Is it INTEGER? Does it allow NULL values?

[rhodesa]

set it to NULL instead of an empty string:

 

INSERT INTO tableName (field1,field2,amount) VALUES ('abc','def',NULL);

or, just leave it out of the list:

INSERT INTO tableName (field1,field2) VALUES ('abc','def');

[Mchl]

That's assuming, that NULL is valid for this field.

[revraz]

IF statements require two == not one

 

if($amount == ""){

 

Also, make sure you remove the Default 0 as well as setting it to NULL and it should work.

[rhodesa]

That's assuming, that NULL is valid for this field.

 

Also I have the structure of this field set to Null

[Mchl]

That's assuming I read posts in their entirety.

 

One more thing. Does the field have a default value? If it does, inserting NULL into it, will in fact insert default value.

[SocomNegotiator]

If you use NULL in your query it should work.

 

UPDATE table SET column = NULL WHERE id = 1

 

Ok yes it is an Integer that is set to NULL. I tried $amount == "" and it did not work.

Ok that is for an update...now if I have an INSERT like this

 

$db->query("INSERT INTO guide_order (item_id, amount, user_id, priority) VALUES ( '$item_id', '$amount', '$user_id', '$num')") or die('Error, query failed');

 

Now you notice that I have $amount...could I change that to NULL? However, with that if the person enters in an amount I want it put the amount they entered into the database. So I can't use NULL here, because no matter if they left it blank or entered in something they would always get nothing.

[Mchl]

The simplest way. Note that I dropped '' around $amount in query

 

if($amount == "") $amount = "NULL";
$query = "INSERT INTO guide_order (item_id, amount, user_id, priority) VALUES ( '$item_id', $amount, '$user_id', '$num')";

[SocomNegotiator]

The simplest way. Note that I dropped '' around $amount in query

 

if($amount == "") $amount = "NULL";
$query = "INSERT INTO guide_order (item_id, amount, user_id, priority) VALUES ( '$item_id', $amount, '$user_id', '$num')";

 

Sweet stuff that right there worked. Thanks a lot everyone for your help.

[rhodesa]

I would do this:

 

Set the field to allow NULL and set the default value to NULL. Then use this:

<?php
$data = array(
  'item_id' => $item_id,
  'user_id' => $user_id,
  'priority' => $num,
);
if(!empty($amount))
  $data['amount'] = $amount;
$sql = "INSERT INTO `guide_order` (`".implode("`,`",array_keys($data))."`) VALUES ('".implode("','",$data)."')";
$db->query($sql) or die('Error, query failed');
?>

[SocomNegotiator]

I would do this:

 

Set the field to allow NULL and set the default value to NULL. Then use this:

<?php
$data = array(
  'item_id' => $item_id,
  'user_id' => $user_id,
  'priority' => $num,
);
if(!empty($amount))
  $data['amount'] = $amount;
$sql = "INSERT INTO `guide_order` (`".implode("`,`",array_keys($data))."`) VALUES ('".implode("','",$data)."')";
$db->query($sql) or die('Error, query failed');
?>

 

Yeah I need to read up on the whole implode thing. I use arrays, but I don't use them as often as I should.

[rhodesa]

I like that method cus it keeps the SQL flexible....2 columns or 20 columns, it's the same statement to make the SQL

[SocomNegotiator]

I like that method cus it keeps the SQL flexible....2 columns or 20 columns, it's the same statement to make the SQL

 

 

Yeah I think I understand the query...except for one thing

 

('".implode("','",$data)."')

 

Why are their two commas? I know one to separate each value, but the other I am not sure...

[Mchl]

The other to separate arguments of implode() function.

 

It's like

 

$separator = "','"
$dataFields = "('".implode($separator,$data)."')";