我正在创建一个页面，用户可以在其中计算他们的BMI，然后将其保存到他们的个人资料中。首先，我验证BMI。但是，当我现在执行此计算时，它将"0.99"插入数据库而不是正确的 BMI 值。我一直在调试，并认为它与数据库的连接有关（尝试将其移动到脚本的其他区域，但它没有区别）。
代码如下：
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" />
<title>Untitled Document</title>
</head>
<link rel="stylesheet" href="css.css" type="text/css" />
<body>
<?php
error_reporting(E_ALL &~ E_NOTICE);
// Start the session
session_start();
// Make sure the browser is transmitting in UTF-8
header('Content-type: text/html; charset=utf-8');
// Clear the error message
$error_msg = "";
if (isset($_SESSION['user_id']))
echo $_SESSION['user_id'];
$dbc = mysqli_connect('localhost', 'root', 'root', 'help_me_be_healthy') or die("Error " . mysqli_error($dbc));
mysqli_set_charset($dbc, "utf8");
if(isset($_POST['submit']))
{
$bmi=0;
$kg=$_POST['kg'];
$mt=$_POST['mt'];
if(empty($kg) || empty($mt))
{
echo "<label class='err'><center>All fields are required</center></label>";
include("index.php");
}
else if(!is_numeric($kg) && !is_numeric($mt) )
{
echo "<label class='err'>Please enter valid data.</label>";
include("index.php");
}
else
{
$bmi = $kg/($mt*$mt);
$bmi=round($bmi,2);
if ( $bmi <= 18.5 )
{
echo "Your BMI is " .$bmi." which means you are underweight";
}
else if ( $bmi>18.5 && $bmi <= 24.9) {
echo "Your BMI is ".$bmi." which means you are normal";
}
else if ( $bmi>29.9 && $bmi> 24.9 ) {
echo "Your BMI is ".$bmi." which means you are overweight";
}
else if ( $bmi >29.9 && $bmi<=39.9 ) {
echo "Your BMI is ".$bmi." which means you are obese";
}
else
{
echo "You are morbidly obese.";
}
include("index.php");
//$query = "UPDATE `users` SET `user_bmi`= '$bmi'
//WHERE `user_id` = ($_SESSION = ['user_id'])";
//echo $_SESSION['user_id'];
//if (!isset($_GET['user_id'])) {
//$query = "SELECT * FROM 'users'";
$query = "UPDATE `users` SET `user_bmi`= '$bmi' WHERE `user_id` = '" . $_SESSION['user_id'] . "'";
//}
//else {
// $query = "UPDATE `users` SET `user_bmi`= '$bmi' WHERE `user_id` = '" . $_GET['user_id'] . "'";
//}
$data = mysqli_query($dbc, $query);
$row = mysqli_fetch_assoc($data);
print "'n----'nLookup:'n";
print "Num rows: " . mysqli_num_rows($data);
print "'n";
print_r($row);
print '</pre>';
return;
}
}
?>
</body>
</html>
任何帮助将不胜感激：）
莎拉
假设BMI计算正确/显示，并且user_bmi列是浮点/双精度/数字/小数，则UPDATE不需要在值两边加上引号，因此SQL应该是：
$query = "UPDATE `users` SET `user_bmi`=$bmi WHERE `user_id`=".
$_SESSION['user_id'];
（user_id我的也不需要转义，这取决于它是数字还是字符串）
此外，您无法从更新 SQL 命令获取查询结果 （fetch_assoc） ...如果您想知道受影响的行数，请使用mysqli_affected_rows：
print "Num rows: ".mysqli_affected_rows($dbc);
是什么让你认为BMI不正确，你确定user_id是正确的，你如何查看数据库以确定存储的内容？
更新的代码打印输出代码：
if (!mysqli_query($dbc,$query)) {
echo "Failed to store";
}
echo "<pre>'n----'nLookup:'nQuery:$query'n".
"Num rows:".mysqli_affected_rows($dbc)."'n</pre>'n";