简单计算mysql sums和php。 怎么做？

I need to do a computation within my website. I have all parameters but couldn't figure out how to combine them to one result.

Please help me to solute this!

I get the data from mysql database: (shorted)

   <?php
     $res = mysql_query('SELECT SUM(status) FROM ' . 'success_rate', $con);
        if ($row = mysql_fetch_array($res, MYSQL_NUM))
        {
           $rate = trim($row[0]);    ?>

<?php
    $res = mysql_query('SELECT Count(*) FROM ' . 'user_registration', $con);
        ?>

So i get 2 classic params

What I need is to have just one Number in the end. This is how the computation shall work:

((<?= $status ?> / <?= $2nd ?>)*100)-200   =  result

Would appreciate your help.

There are a few problems. First, the mysql extension is depreciated. Use mysqli instead. When you do that you change mysql_fetch_array($res, MYSQL_NUM) to mysqli_fetch_array($res).

Next, you need to close the if statement brackets. You only have an opening bracket.

That second code snippet is a syntax errpr. Do this: $result = (($status / $second)*100)-200

Beyond that, I don't know what else you want because you haven't given enough detail.

You need to fetch the second query also:

$rate = 0;
$count = 0;

$res = mysql_query('SELECT SUM(status) FROM success_rate', $con);
$row = mysql_fetch_array($res);
$rate = $row[0];

$res = mysql_query('SELECT Count(*) FROM user_registration', $con);
$row = mysql_fetch_array($res);
$count = $row[0];

if ($count != 0) {
    echo (($status / $count) * 100) - 200;
} else {
    echo 'Count was 0';
}

• Do not use mysql functions because the are deprecated. Use mysqli or PDO instead.

• Use an IDE to inspect your syntax errors in your code.

If you want to shorten the code by returning the result with one query, you could do it this way:

$res = mysql_query("SELECT (((SUM(status) / (SELECT Count(*) FROM user_registration)) * 100) - 200) as result FROM success_rate") or die (mysql_error());

Note however: if the second parameter is smaller than the first, you will get a negative number in the end, because you're subtracting 200 in the end.

For example: IF SUM(status) = 10 AND Count(*) = 100, THEN your result is -190

((10/100)*100)-200 = -190