Select Data

If you need to fetch data from a MySQL database in your PHP applications, you'll rely heavily on SQL’s SELECT statement. The SELECT statement enables you to retrieve specific data from tables and use it in your application.

In this article, You will understand everything you need to know about how to select data—using both procedural and object-oriented methods. You will also learn more about PDO (PHP Data Objects), which is a great alternative for working with databases.

Basic Syntax of the SQL SELECT Statement

The below syntax show you how to write the SELECT statement in SQL:

SELECT column1, column2, ... FROM table_name;

This simple command retrieves data from the specified columns of a table. If you want to fetch everything, you can use the * wildcard:

SELECT * FROM table_name;

This command helps you to pull all data from the table, which can be handy, but for some reason, you will often want to be more specific.

Let's move on to the following section to see how it works with PHP.

Select Data Using MySQL in PHP

You can start running SQL queries. Here’s how you can select data using the mysqli extension:

$db_server_name= "localhost";
$db_username = "username";
$db_password = "password";
$db_dbname = "database_name";

$condb = new mysqli($db_server_name, $db_username , $db_password , $db_dbname );

if ($condb->connect_error) {
   die("Unable to Establish Database Access:". $condb->connect_error);
}

$sql = "SELECT * FROM users";
$dbresult= $condb->query($sql);

if ($dbresult->num_rows > 0) {
    while($row = $dbresult->fetch_assoc()) {
        echo "rec_id: " . $row["user_id"]. " - Name: " . $row["name"]. "<br>";
    }
} else {
    echo "0 results";
}

This example retrieves all rows from the users table and displays the id and name fields. The fetch_assoc() function retrieves a result row from database as an associative array.

Procedural Method for Data Selection

You can connect to the database and fetch data in a similar way. Here is an example:

$condb= mysqli_connect($db_server_name, $db_username, $db_password, $db_dbname);

if (!$condb) {
    die("Unable to Establish Database Access:" . mysqli_connect_error());
}

$sql = "SELECT * FROM users";
$dbresult= mysqli_query($condb, $sql);

if (mysqli_num_rows($dbresult) > 0) {
    while($row = mysqli_fetch_assoc($dbresult)) {
        echo "id: " . $row["id"]. " - Name: " . $row["name"]. "<br>";
    }
} else {
    echo "0 results";
}

mysqli_close($condb);

This syntax might be simple, but it does the job perfectly. Just do not forget to close the connection yourself once you are done fetching the data.

Using PDO to Select Data

PDO is considered more secure because it supports prepared statements, helping protect against SQL injection. Here’s an example using PDO:

try {
    $condb = new PDO("mysql:host=$db_server_name;dbname=$db_name", $db_username, $db_password);
    $condb->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
    
    $stmt = $condb->prepare("SELECT id, name FROM users");
    $stmt->execute();
    
    $dbresult= $stmt->fetchAll();
    
    foreach ($dbresultas $row) {
        echo "id: " . $row['id'] . " - Name: " . $row['name'] . "<br>";
    }
}
catch(PDOException $e) {
    echo "Error: " . $e->getMessage();
}
$condb= null;

Let's see in the following example how to handle results from the query.

Fetching Results from the Query

After executing the SELECT statement, you will want to handle the results. PHP helps you to use several ways to fetch the results:

Here’s an example of using these methods:

while ($row = $dbresult->fetch_assoc()) {
    echo $row["id"] . " " . $row["name"] . "<br>";
}

while ($row = $dbresult->fetch_array()) {
    echo $row[0] . " " . $row[1] . "<br>";
}

while ($row = $dbresult->fetch_object()) {
    echo $row->id . " " . $row->name . "<br>";
}

Each of these methods provides a different way of accessing the data depending on how you want to structure your result handling.

Select Data Using Object-Oriented in MySQL Using PHP

The object-oriented method with MySQLi allows you to use classes and objects, which can feel more organized. Here's an example:

$condb= new mysqli($db_server_name, $db_username, $db_password, $db_dbname);

if ($condb->connect_error) {
    die("Unable to Establish Database Access:". $condb->connect_error);
}

$sql = "SELECT * FROM users";
$dbresult= $condb->query($sql);

if ($dbresult->num_rows > 0) {
    while($row = $dbresult->fetch_assoc()) {
        echo "rec_id: " . $row["user_id"]." - Name: " . $row["name"]. "<br>";
    }
} else {
    echo "0 results";
}

$condb->close();

It's more organized and readable, especially if your project has complex database interactions.

Let's see how to display the data in an HTML table.

Displaying Data in an HTML Table

You can display it in an HTML table for a neat presentation once you have the data:

echo "<table border='1'>
<tr>
<th>ID</th>
<th>Name</th>
</tr>";

while($row = $dbresult->fetch_assoc()) {
    echo "<tr><td>" . $row["id"]. "</td><td>" . $row["name"]. "</td></tr>";
}

echo "</table>";

This code will create a simple table to display the results in a tabular format.

Let's summarize it.

Wrapping Up

Getting data from a MySQL database with PHP might seem a bit confusing at first, but once you understand the steps, it will be easy. So if you like using of mysqli or PDO, getting the basics down will help you create secure database-driven projects.

Here is a quick recap of what we explained:

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