php mysql从数据库获取变量数据并计算 [英] php mysql get variable data from database and calculate

问题描述

你好，我的溢出者有一个问题，我想从数据库中获取变量数据"$ b，$ d，$ f，$ h"，然后计算出来 这是我的例子

hello fellow overflower i have problem iwant to get variable data "$b ,$d, $f,$h" from database and then calculate it here my example

<?php
    $host="localhost";
    $username="root";
    $password="root";
    $db_name="cbrteh"

    mysql_connect("$host", "$username", "$password")or die("cannot connect");
    mysql_select_db("$db_name")or die("cannot select DB");

    $b= mysql_query("SELECT bobot FROM atribut where id= 1"); 
    ($row = mysql_fetch_assoc($b));
    $row["bobot"];
    $d= mysql_query("SELECT bobot FROM atribut where id= 2"); 
    ($row = mysql_fetch_assoc($d));
     $row["bobot"];
    $f= mysql_query("SELECT bobot FROM atribut where id= 3"); 
    ($row = mysql_fetch_assoc($f));
    $row["bobot"];
    $h= mysql_query("SELECT bobot FROM atribut where id= 4"); 
    ($row = mysql_fetch_assoc($h));
    $row["bobot"];
    $calc = $b+$d+$f+$h;
    echo $calc;

我的脚本正确吗 数据库上的值是50,50,50,50，所以值必须是200 但是我从echo $ calc得到的值;是22

is my script right the value on database are 50,50,50,50 so the value must be 200 but the value i got from echo $calc; is 22

推荐答案

尝试一下:

$b= mysql_query("SELECT bobot FROM atribut where id= 1");
$row = mysql_fetch_row($b);
$b   = $row[0]; 
$d= mysql_query("SELECT bobot FROM atribut where id= 2");
$row = mysql_fetch_row($d);
$d   = $row[0];
[...] // repeat for $f and $h
$calc = $b + $d + $f + $h;
echo($calc);

或者，也许使用任何更合适的代码:

Or, maybe used any more appropriate code :

$b= mysql_query("SELECT SUM(bobot) as calc FROM atribut WHERE id IN (1,2,3,4)");
$row = mysql_fetch_row($b);
$calc = $row[0];
echo($calc);

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