Using UPDATE and SET to add or subtract a value

[pquinn]

Hello,

 

Hope I am in the right part of the forum for this

 

I have been teaching my self php for a few weeks now and I have hit a brick wall

 

Using the following code I have been able to add or subtract values within a column in my SQL table:

 

// Connect to server and select databse.
mysql_connect("$host", "$username", "$password")or die("cannot connect");
mysql_select_db("$db_name")or die("cannot SELECT DB");

//Add query
$sql = mysql_query("UPDATE UserList SET Rewards = (Rewards + 10) WHERE Username LIKE '%$add%'");

 

But for the life me I can not figure out how to use a List/Menu with values of 10, 20, 30 & 40 to be the amount added rather than having a default amount in the query.

 

I tried:

 

// Connect to server and select databse.
mysql_connect("$host", "$username", "$password")or die("cannot connect");
mysql_select_db("$db_name")or die("cannot SELECT DB");

//Add query
$sql = mysql_query("UPDATE UserList SET Rewards = (Rewards + '%$addvalue%') WHERE Username LIKE '%$add%'");

 

Where 'addvaule' was the id for the value:

 

 
<form action="add_points.php" method="post" class="style13">
<input name="add" type="text" id="add" />
</label><label>
<select name="addvalue" id="addvalue">
<option value="10">10</option>
<option value="20">20</option>
<option value="30">30</option>
<option value="40">40</option>
</select>
<input type="submit" name="submit" value=" Reward " />
</form>

 

Hope I am making sense head is going to explode lol,.

 

Any help and advice would be very much appreciated.

 

P Quinn

[Zane]

$_POST['addvalue']

[pquinn]

Hi,

 

Thanks I have adjusted my code to be;

 

<?php $add = $_POST['add']; ?>
<?php $addvalue = $_POST['addvalue']?>
<?php
// Database details
$host=""; // Host name
$username=""; // Mysql username
$password=""; // Mysql password
$db_name=""; // Database name
$tbl_name="UserList"; // Table name

// Connect to server and select databse.
mysql_connect("$host", "$username", "$password")or die("cannot connect");
mysql_select_db("$db_name")or die("cannot SELECT DB");

//Add query
$sql = mysql_query("UPDATE UserList SET Rewards = (Rewards + '%$addvaule%') WHERE Username LIKE '%$add%'");

?>

 

And the action is processed but the value does not update, any advice would be great.

 

Many thanks,

 

P Quinn

[sasa]

$sql = mysql_query("UPDATE UserList SET Rewards = (Rewards + $addvaule) WHERE Username LIKE '%$add%'");

[pquinn]

Hi sasa,

 

Thank you so much it is working perfectly now I will cease smacking my head off the wall hehe

 

[pquinn]

hmmmm

 

The value will now update correctly but I have three columns: Rewards, Sanctions and TotalPoints

 

The values for Rewards and Sanctions will update correctly but the Total Points will not.

 

On page subtract_points.php the code I have updated to look like:

 

<?php 
$subtract = $_POST['subtract'];
$subtractvalue = $_POST['subtractvalue '];

// Database details
$host=""; // Host name
$username=""; // Mysql username
$password=""; // Mysql password
$db_name=""; // Database name
$tbl_name="UserList"; // Table name

// Connect to server and select databse.
mysql_connect("$host", "$username", "$password")or die("cannot connect");
mysql_select_db("$db_name")or die("cannot SELECT DB");


//Update Total Points query
$sql = mysql_query("UPDATE UserList SET TotalPoints = (TotalPoints - $subtractvalue) WHERE Username LIKE '%$subtract%'");

?>

 

Basically as I reward or sanction I want the total points to reflect only the points removed so if I had picked 30 rewards and rewards the Rewards to be at 30 and TotalPoints to be at 30, but if i remove 40 I want the TotalPoints to show -10. 

 

It was working before I used the list menu that is working fine now for adding and subtracting. So close any help would be great

 

Many Thanks,

 

P Quinn

[pquinn]

Got it

 

was missing something, but you know i cant see the difference from whatever I just  did lol

 

Thanks again to all who helped