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PHP Adding/Subtracting

Hi experts,

I have a database table that looks like the following.

Customer Jan        Feb     March    April     May   June July Aug Sep etc
Jan          10.12    11.00    15.00    12.56    -36.25   ETCC

As you can see there is a minus under may of -36.25...is there away of setting a negative value to the database?
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NeoAshura
Asked:
NeoAshura
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1 Solution
 
Beverley PortlockCommented:
What do you mean by this "is there away of setting a negative value to the database?". Are you trying to say that you cannot store a negative number in the database?

Make sure the DB column is SIGNED or at least that it is not UNSIGNED
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Cornelia YoderArtistCommented:
Just give your database field the characteristic of SIGNED, and you can put negative numbers into it.
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NeoAshuraAuthor Commented:
sorry bad english they are set as negative, and ive eneted the value as -36 so should recongise it, i just dont know how to get the result (sum) of the columns at the end in php
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Beverley PortlockCommented:
"...they are set as negative.."

What are set as negative? I'm sorry but I still do not understand what the problem is. I can see that the sample table above has -36.25 in it, but I'm not clear what you are trying to do with it.

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NeoAshuraAuthor Commented:
im trying to add the posotives in php with the data from the database

e.g

10+10+10 but then need to -minus the negatives for example

10+10+10-36= £-6
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Beverley PortlockCommented:
Can you post the code that's not doing the adding correctly? It should just be simple arithmetic operations which is why I'm struggling to see where the problem would lie.
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Cornelia YoderArtistCommented:
If the negative value is already in the database, you can just use SUM in MySQL or simple arithmetic in php.

$a = 3 + 2 - 4;

will give you $a = 1
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NeoAshuraAuthor Commented:
here it is sorry for late reply i keep getting unidentified index maybe im not defineing the variables?

if thats the case how would i add the columns jan and feb?

code is attached thanks again
<?php
session_start();
ob_start();
include 'myphp.php';
?>
<?php
$val = $_GET['val'];
$sql = "SELECT * FROM bill_detail2009  WHERE mobile_number = '" . $val . "'";

$first_number = $_GET['Jan09'];
$second_number = $_GET['Feb09'];
$sum_total = $first_number + $second_number;

$direct_text = 'The two variables added together = ';

print ($direct_text . $sum_total);

?>

Open in new window

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Beverley PortlockCommented:
You're not processing the database values or even accessing the database. I don't even know if you have establised a database connection at this point.

The following UNTESTED code should be closer to what you need but without knowing you database table structure I can only guess....

<?php
session_start();
ob_start();
include 'myphp.php';
?>
<?php
$val = $_GET['val'];
$sql = "SELECT * FROM bill_detail2009  WHERE mobile_number = '" . $val . "'";



$rs = mysql_query( $sql );

if ( $rs ) {

     if ( mysql_num_rows($rs) == 0 )
          echo "NO data to process";
     else {
          $rw = mysql_fetch_assoc( $rs );

          $sum_total = $rw['Jan09'] + $rw['Feb09'];
     }
}
else
     echo "Query failed " . mysql_error();
     



$direct_text = 'The two variables added together = ';

print ($direct_text . $sum_total);

?>

Open in new window

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NeoAshuraAuthor Commented:
myphp was my connection file and thanks it worked ok
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