Need to calaculate new number from old number and put in to different row

[silo23]

Actual output required is monthly miles saved back to db then out to chart.

Current problem, using kduv's solution using the db and PHP code (post 16 above), I can get the code to save monthly_miles back to db on my test server (XAMPP) but when I upload it and try it on my live sever it doesn't work.

[r937]

"doesn't work" is not a recognized error message

[silo23]

It may not be a recognized error message, but it is an accurate description of what didn't happen.

Using kduv's code, this works on my XAMPP setup but not on my hosting server.

    $last_odometer = ($i == 0) ? $columns['odometer'] : $rows[$row - 1]['odometer'];
    $month_total = $columns['odometer'] - $last_odometer;

Unfortunately, for the life of me, I cannot understand how the above piece of code saves it's output back to the monthly_mileage column.

[silo23]

I've placed the code,

<?php error_reporting(E_ALL);
ini_set('display_errors', 1); ?>

at the beginning of the page to try and track errors and i get this error back

Warning: Invalid argument supplied for foreach() in C:\xampp\htdocs\test\Mileage3_output.php on line 95

Still using kduv's code from post 16. Any help, observations or quips more than welcome.

[Cups]

foreach ($rows as $row => $columns) 

If that is the offending line then it means that $rows is not a valid array. Its probably not an array at all, so at this point you have to start investigating why your two setups are different.

Check the files closely and if you do not spot something obvious then a good bet is that either your db credentials on your live server are incorrect, OR you do not have any matching data in your database OR an include file is not being found.

Otherwise start by adding the line:

var_dump($rows); 

and work you way back through the variables till you get proof of where the error is occurring.

[silo23]

Hi, in kduv's original code it says

$rows = ''; // array of rows from database results

Which I might be supposed to fill in or not. I've been reading up and googling as much as I can but I'm afraid I don't know.

[silo23]

Just to say thanks for everyone's help (especially Cups) there is now a working solution.