PHP MySql prepared statements ... How to UPDATE DB, Adding to value already stored

Question

So just converting old sql statements into prepared statements

So how do I add to a value already stored in a database?

in old terms I did this:

$sql = "UPDATE `table` SET `PT` = PT+$PaymentGross ... ";

but how do you accomplish same in prepared statements?

like so:

$sql = "UPDATE `table` SET `PT` = PT+? ...  ";

or like so:

$stmt->bind_param("i",PT+$PaymentGross ... );

couldn't find any info, or perhaps couldn't punch right keywords into google

So what really is your problem? Please provide more detail so that we can help. — YATO
– YATO, Commented Jul 29, 2017 at 11:03
Sorry I tried the statement before it wasn't working. I have just notice that the mistake was elsewhere on the statement line. I assumed I had typed UPDATE table SET PT = PT+? in wrong. My bad, silly mistake — James
– James, Commented Jul 29, 2017 at 11:06

vjy tiwari · Accepted Answer · 2017-07-29 20:41:34Z

2

You can try this way

$sql = "UPDATE `table` SET `PT`=SUM(`PT`+?) WHERE id=?";

    $stmt = $db->prepare($sql);

    // This assumes the PT is int `d` and id is int `d`


    $stmt->bind_param('dd', $PaymentGross, $id);
    $stmt->execute();

    if ($stmt->errno) {
      echo "FAILURE!!! " . $stmt->error;
    }
    else echo "Updated {$stmt->affected_rows} rows";

    $stmt->close();

answered Jul 29, 2017 at 20:41

vjy tiwari

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