PHP MySQL Connection Issue: Unable to Retrieve Data from Dat

[joel2]

I'm facing a problem while trying to establish a connection between PHP and MySQL to retrieve data from a database. I'm using the mysqli extension for PHP, but I'm not able to fetch the expected results. Here's a simplified version of my code:

Code: Select all

<?php
$servername = "localhost";
$username = "root";
$password = "";
$database = "mydatabase";

// Create connection
$conn = new mysqli($servername, $username, $password, $database);

// Check connection
if ($conn->connect_error) {
    die("Connection failed: " . $conn->connect_error);
}

// Attempt to fetch data
$query = "SELECT * FROM mytable";
$result = $conn->query($query);

if ($result->num_rows > 0) {
    while($row = $result->fetch_assoc()) {
        echo "ID: " . $row["id"] . " - Name: " . $row["name"] . "<br>";
    }
} else {
    echo "No data found.";
}

$conn->close();
?>


When I run this script, I get the "No data found." message even though I have data in the mytable table. I've confirmed my database credentials and table name, but I can't figure out what's causing this issue.

Could someone please review my code and provide insights into what might be causing this problem? Is there a common mistake I might be overlooking or any debugging steps I should take to diagnose the issue? Any help would be greatly appreciated. Thank you!

[Nobbie]

Here's a simplified version of my code:

What does that mean? Did you run that simplified script as well?

[gracemartin]

It seems like your code is structured correctly for connecting to the MySQL database and executing the query. Since you're getting the "No data found." message even though you have data in the table, the issue might be related to the SQL query itself or the data in the table.

Here are a few steps you can take to troubleshoot and debug the issue:

Verify Table and Column Names: Double-check that the table name ("mytable") and column names ("id" and "name") in your SQL query match the actual names in your database schema. Even a small typo can cause the query to return no results.

Check Data Existence: Confirm that there are indeed records in the "mytable" table. You can do this directly in MySQL by running a SELECT * FROM mytable query in your database management tool or by using phpMyAdmin.

Error Handling: Add error handling to your code to see if there are any errors occurring during the execution of the query. You can use $conn->error to get the specific error message if there's an issue with the query execution.


if ($result === false) {
echo "Error: " . $conn->error;
} else {
// Proceed with fetching data
}

Debugging Query: Print out the generated SQL query to ensure it's constructed correctly. This can help you identify any issues with the query itself.

echo "Query: " . $query;

Test with a Simple Query: Try running a simpler query, such as SELECT 1, to see if you can retrieve any data from the database. If this query works, it might indicate a problem with your original query.

Permissions:] Make sure that the MySQL user specified in your connection credentials has the necessary permissions to access the database and query the table.

Several websites provide free online training:

1. https://www.javatpoint.com/sql-tutorial
2. https://iqratechnology.com/academy/sql-training/