PHP函数无法连接到数据库以调用查询

Question

I have three .php files.

db_conx.php

$db_conx = mysqli_connect("localhost", "admin", "admin", "gestiune");
    // Evaluate the connection
    if (mysqli_connect_errno()) {
        echo mysqli_connect_error();
        exit();
}

functions.php

function deplata($pid){
        $sqlp = "SELECT * FROM plati WHERE user_id";
        $queryp = mysqli_query($db_conx, $sqlp);
        $type = "day";
        $payments = 0;
        $salary = 80;
        $days = 4;
        $topay = 0;
        while($getplata = mysqli_fetch_assoc($queryp)){
            $plati += $getplata['valoare'];
        }
        if($tip == "day"){
            $topay = $days * $salary;
        }

        return $topay;
}

And I have the index.php file to call the files and use them.

include_once("php_includes/db_conx.php");
include_once("php_includes/functii.php");

$salariu = deplata(5);
echo $salariu;

The problem is that it will not connect to the database and it returns some errors:

Notice: Undefined variable: db_conx in D:\xampp\htdocs\manager\pages\php_includes\functions.php on line 5

Warning: mysqli_query() expects parameter 1 to be mysqli, null given in D:\xampp\htdocs\manager\pages\php_includes\functions.php on line 5

Warning: mysqli_fetch_assoc() expects parameter 1 to be mysqli_result, null given in D:\xampp\htdocs\manager\pages\php_includes\functions.php on line 11

And then it prints the value (since it does not currently use database any values). What I tried: I tried to put the functions.php content directly into the index.php file, I tried to call the db_conx.php file inside the functions.php file.

Answer 1

You need to define the value the in function.php.checkout the below code

function.php

function deplata($pid){

   global $db_conx;

    $sqlp = "SELECT * FROM plati WHERE user_id";
    $queryp = mysqli_query($db_conx, $sqlp);
    $type = "day";
    $payments = 0;
    $salary = 80;
    $days = 4;
    $topay = 0;
    while($getplata = mysqli_fetch_assoc($queryp)){
        $plati += $getplata['valoare'];
    }
    if($tip == "day"){
        $topay = $days * $salary;
    }

    return $topay;
}

index.php

Check the typo mistake in index.php

include_once("php_includes/function.php");