PHP Get SQL Query Results

Getting SQL query results in PHP is a common task when working with a database. In this tutorial, we will use MySQLi, a PHP extension designed to work with MySQL databases.

Firstly, you'll need to establish a connection to your MySQL database using mysqli_connect():

// Database credentials
$db_host = 'localhost';
$db_user = 'username';
$db_pass = 'password';
$db_name = 'database_name';

// Create connection
$conn = mysqli_connect($db_host, $db_user, $db_pass, $db_name);

// Check connection
if (!$conn) {
    die("Connection failed: " . mysqli_connect_error());
}

Next, you can use a SELECT query to get data from your database:

// SQL query
$sql = "SELECT * FROM table_name";

// Execute query and get result
$result = mysqli_query($conn, $sql);

if ($result) {
    // Fetch all rows as an associative array
    while($row = mysqli_fetch_assoc($result)) {
        echo "ID: " . $row["id"]. " - Name: " . $row["name"]. "<br>";
    }
} else {
    echo "Error: " . mysqli_error($conn);
}

In this example, mysqli_query() executes the SQL query and returns a result set. Then, mysqli_fetch_assoc() is used in a while loop to fetch each row from the result set as an associative array. The array keys are the column names and the array values are the data in each row.

Finally, don't forget to close the connection when you're done:

// Close connection
mysqli_close($conn);

This is a simple example. Depending on your needs, you may want to handle errors more gracefully, escape your SQL queries to prevent SQL injection, fetch rows as objects instead of arrays, or use prepared statements for better performance and security.

Note: While MySQLi is a powerful extension, many developers prefer to use the PDO (PHP Data Objects) extension instead because it provides a more consistent interface for working with different types of databases.

Retrieving data from MySQL database in PHP:

Use mysqli_query() to execute SQL queries and retrieve data.

<?php
$mysqli = new mysqli('localhost', 'username', 'password', 'database');

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

// Execute a SELECT query
$result = $mysqli->query('SELECT * FROM users');

// Process the result set
// ...

// Close the connection
$mysqli->close();

Using mysqli_query() in PHP to execute SQL queries:

Execute various SQL queries using mysqli_query().

<?php
// Execute a SELECT query
$result = $mysqli->query('SELECT * FROM products');

// Execute an INSERT query
$insertResult = $mysqli->query('INSERT INTO orders (product_id, quantity) VALUES (1, 10)');

Fetching and displaying SQL query results in PHP:

Fetch and display data from the result set.

<?php
$result = $mysqli->query('SELECT * FROM customers');

while ($row = $result->fetch_assoc()) {
    echo "Name: {$row['name']}, Email: {$row['email']}<br>";
}

Handling SELECT queries with PHP and MySQL:

Handle SELECT queries and process the result set.

<?php
$result = $mysqli->query('SELECT * FROM orders');

if ($result->num_rows > 0) {
    while ($row = $result->fetch_assoc()) {
        // Process each row
    }
} else {
    echo "No results found.";
}

Error handling when getting SQL query results in PHP:

Check for errors and handle them gracefully.

<?php
$result = $mysqli->query('SELECT * FROM customers');

if ($result === false) {
    die('Query failed: ' . $mysqli->error);
}

Binding parameters and executing prepared statements in PHP:

Use prepared statements for improved security and performance.

<?php
$stmt = $mysqli->prepare('SELECT * FROM products WHERE category = ?');
$category = 'Electronics';
$stmt->bind_param('s', $category);
$stmt->execute();

$result = $stmt->get_result();

while ($row = $result->fetch_assoc()) {
    // Process each row
}

Converting SQL results to arrays or objects in PHP:

Convert result sets to arrays or objects for easy manipulation.

<?php
// Convert to associative array
$resultArray = $result->fetch_all(MYSQLI_ASSOC);

// Convert to objects
$resultObject = $result->fetch_object();

Processing and manipulating SQL query results in PHP:

Process and manipulate the result set according to your needs.

<?php
$result = $mysqli->query('SELECT * FROM products');

while ($row = $result->fetch_assoc()) {
    // Process each row
    $productName = $row['name'];
    // ...
}