從常規數字中減去 SUM 值以獲得使用 PHP 的總數

Question

我正在我的應用程序中設置一個“目標”顯示字段。 此示例的目標是 12000 公斤（我們處理電子垃圾）。 我使用 MySQL SUM 函數來統計我的員工輸入的所有權重，現在我想取 12000KG 目標，並將其從 SUM 值中減去以獲得差異，以便員工可以看到他們離實際 12000KG 目標有多遠. 我該怎么做？

 <h3>Target: 12000KG</h3>
           <h3>Current Value: <?php
$dbConnection = new PDO('mysql:dbname=ecemsmaster;host=127.0.0.1;charset=utf8', 'ecemsmaster', 'ecemsmaster');
$dbConnection->setAttribute(PDO::ATTR_EMULATE_PREPARES, false);
$dbConnection->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);

//The COUNT SQL statement that we will use.
$sql = "SELECT MONTH(date), SUM(subgrade + castaluminium + copper + stainlesssteel + plastic + brass + batteries + cables + lowgradePCB + mediumgradePCB + highgradePCB) AS num FROM daily_recyclables where MONTH(date)=MONTH(curdate())";
 
//Prepare the COUNT SQL statement.
$stmt = $dbConnection->prepare($sql);

//Execute the COUNT statement.
$stmt->execute();

//Fetch the row that MySQL returned.
$row = $stmt->fetch(PDO::FETCH_ASSOC);

//The $row array will contain "num". Print it out.
echo $row['num'];
?> KG</h3>
            <h3>Over/Under Target: **-1000KG**</h3>

Answer 1

不確定這是否是正確的方法，但它對我有用。

我剛剛通過 echo $row['num']; 添加了“-12000”；

<?php
$dbConnection = new PDO('mysql:dbname=ecemsmaster;host=127.0.0.1;charset=utf8', 'ecemsmaster', 'ecemsmaster');
$dbConnection->setAttribute(PDO::ATTR_EMULATE_PREPARES, false);
$dbConnection->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);

//The COUNT SQL statement that we will use.
$sql = "SELECT MONTH(date), SUM(subgrade + castaluminium + copper + stainlesssteel + plastic + brass + batteries + cables + lowgradePCB + mediumgradePCB + highgradePCB) AS num FROM daily_recyclables where MONTH(date)=MONTH(curdate())";
 
//Prepare the COUNT SQL statement.
$stmt = $dbConnection->prepare($sql);

//Execute the COUNT statement.
$stmt->execute();

//Fetch the row that MySQL returned.
$row = $stmt->fetch(PDO::FETCH_ASSOC);

//The $row array will contain "num". Print it out.
echo $row['num'];
?> KG</h3>
            <h3>Over/Under Target:  <?php
$dbConnection = new PDO('mysql:dbname=ecemsmaster;host=127.0.0.1;charset=utf8', 'ecemsmaster', 'ecemsmaster');
$dbConnection->setAttribute(PDO::ATTR_EMULATE_PREPARES, false);
$dbConnection->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);

//The COUNT SQL statement that we will use.
$sql = "SELECT MONTH(date), SUM(subgrade + castaluminium + copper + stainlesssteel + plastic + brass + batteries + cables + lowgradePCB + mediumgradePCB + highgradePCB) AS num FROM daily_recyclables where MONTH(date)=MONTH(curdate())";
 
//Prepare the COUNT SQL statement.
$stmt = $dbConnection->prepare($sql);

//Execute the COUNT statement.
$stmt->execute();

//Fetch the row that MySQL returned.
$row = $stmt->fetch(PDO::FETCH_ASSOC);

//The $row array will contain "num". Print it out.
echo $row['num']-12000;
?>