Logout getting PHP Warning: mysqli_query() expects at least 2 parameters, 1 given

Question

I'm new with PHP and I'm trying to solve this problem but I don't know how.

<?php
    session_start();
    require "../config.php";
    $retvaloff = mysqli_query($con);
    session_destroy();
    header("Location: index.php");
?>

PHP Warning: mysqli_query() expects at least 2 parameters, 1 given in logout.php on line 4

As it says, there is only 1 parameter and it must be 2. Which parameter could I add to mysqli_query?

Thanks!

I strongly recommend to use PDO instead of mysqli. Here is a good tutorial https://phpdelusions.net/pdo — Dharman, Apr 20 '20 at 23:06

score 0 · Accepted Answer · edited Apr 20 '20 at 23:04

0

You should send two parameters to mysqli_query:

db connection and
query.

for reference

At this moment you only send db connections to this function.

edited Apr 20 '20 at 23:04

davejal

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answered Apr 20 '20 at 22:31

Mike Foxtech

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score 0 · Answer 2 · answered Apr 20 '20 at 22:32

0

First parameter to the mysqli_query function is your connection resource (I assume $con in your case), second parameter is the query (string).

PS: Make sure to protect against SQL injection.

answered Apr 20 '20 at 22:32

Jeroen van der Laan

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Which link about SQL injection would you suggest? – poteitow Apr 20 '20 at 22:46
1

@JeroenvanderLaan Please do not use `mysqli_real_escape_string()` – Dharman Apr 20 '20 at 23:06

Logout getting PHP Warning: mysqli_query() expects at least 2 parameters, 1 given

2 Answers2