How to Troubleshoot mysqli_query Error in PHP When Using w3schools Tutorial?

Using w3schools Tutorial Results in Error

Question:

Despite following the w3schools tutorial, I'm encountering an error in line 13 (mysqli_query) while attempting to insert data using PHP and MySQL. I've explored StackOverflow but was unable to identify the issue. Can someone assist me in troubleshooting this code?

Answer:

Warning: Avoid relying on w3schools for technical information. Their resources frequently contain inaccuracies.

The error in line 13 is caused by an incorrect parameter passed to mysqli_query. The first parameter should be a connection identifier rather than a connection string.

According to the mysqli_query documentation, the correct format is:

<code class="php">mysqli_query($link, $query);</code>

where:

• $link is the MySQL connection identifier
• $query is the SQL query to be executed

Modified Code:

<code class="php"><?php // Establish a MySQL connection
$mysqli = mysqli_connect("localhost", "root", "", "web_table");

// Check for connection errors
if (mysqli_connect_errno()) {
    echo "Failed to connect to MySQL: " . mysqli_connect_error();
    exit;
}

// Execute the INSERT query, ensuring the connection identifier is used
$result = mysqli_query($mysqli, 'INSERT INTO web_formitem (ID, formID, caption, key, sortorder, type, enabled, mandatory, data) VALUES (105, 7, Tip izdelka (6), producttype_6, 42, 5, 1, 0, 0)');

// Check for insert success
if ($result) {
    echo "<p>Insert successful";
} else {
    echo "<p>Insert failed</p>";
}</code>

Note: Additionally, enclose column names in backticks (`) since some of your column names are reserved words in MySQL.

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