php mysql select

Select Data From a MySQL Database

The SELECT statement is used to select data from one or more tables:

SELECT column_name(s)

FROM table_name

or we can use the * character to select ALL columns from a table:

SELECT *

FROM table_name

To learn more about SQL, please visit our SQL tutorial.

Select Data With MySQLi

The following example selects the id, firstname and lastname columns from the MyGuests

table and displays it on the page:

Example (MySQLi Object-oriented)

<?php$servername = "localhost";$username = "username";$password = "password";$dbname = "myDB";// Create connection$conn = new mysqli($servername, $username, $password, $dbname);// Check connectionif ($conn->connect_error) {

  die("Connection failed: " . $conn->connect_error);

} $sql = "SELECT id, firstname, lastname FROM MyGuests";$result = $conn->query($sql);if ($result->num_rows > 0) {  // output data of each row

  while($row = $result->fetch_assoc()) {    echo "id: " . $row["id"]. " - Name: " . $row["firstname"]. " " . $row["lastname"]. "<br>";

  }} else {  echo "0 results";}

$conn->close();

?>

Code lines to explain from the example above:

First, we set up an SQL query that selects the id, firstname and lastname columns from the MyGuests

table. The next line of code runs the query and puts the resulting data into a

variable called $result.

Then, the function num_rows() checks if there are more than zero

rows returned.

If there are more than zero rows returned, the

function fetch_assoc() puts all the results into an associative array that we can loop

through. The while() loop loops through the result set and outputs the data from

the id, firstname and lastname columns.

The following example shows the same as the example above, in the MySQLi

procedural way:

Example (MySQLi Procedural)

<?php$servername = "localhost";$username = "username";$password = "password";$dbname = "myDB";// Create connection

$conn = mysqli_connect($servername, $username, $password, $dbname);

// Check connection

if (!$conn) {

  die("Connection failed: " . mysqli_connect_error());}$sql = "SELECT id, firstname, lastname FROM MyGuests";$result = mysqli_query($conn, $sql);if (mysqli_num_rows($result) > 0) {

  // output data of each row  while($row = mysqli_fetch_assoc($result)) {    echo "id: " . $row["id"]. " - Name: " . $row["firstname"]. " " . $row["lastname"]. "<br>";

  }} else {  echo "0 results";}

mysqli_close($conn);

?>

You can also put the result in an HTML table:

Example (MySQLi Object-oriented)

<?php$servername = "localhost";$username = "username";$password = "password";$dbname = "myDB";// Create connection$conn = new mysqli($servername, $username, $password, $dbname);// Check connectionif ($conn->connect_error) {

  die("Connection failed: " . $conn->connect_error);

} $sql = "SELECT id, firstname, lastname FROM MyGuests";$result = $conn->query($sql);if ($result->num_rows > 0) {

  echo "<table><tr><th>ID</th><th>Name</th></tr>";

  // output data of each row  while($row = $result->fetch_assoc()) {    echo "<tr><td>".$row["id"]."</td><td>".$row["firstname"]." ".$row["lastname"]."</td></tr>";

  }  echo "</table>";} else {  echo "0 results";}

$conn->close();

?>

Select Data With PDO (+ Prepared Statements)

The following example uses prepared statements.

It selects the id, firstname and lastname columns from the MyGuests table and

displays it in an HTML table:

Example (PDO)

<?phpecho "<table style='border: solid 1px black;'>";

echo "<tr><th>Id</th><th>Firstname</th><th>Lastname</th></tr>";class TableRows extends RecursiveIteratorIterator {

  function __construct($it) {     parent::__construct($it, self::LEAVES_ONLY);

  }

  function current() {    return "<td style='width:150px;border:1px solid black;'>" . parent::current(). "</td>";

  }  function beginChildren() {     echo "<tr>";

  }   function endChildren() {     echo "</tr>" . "\n";

  } } $servername = "localhost";

$username = "username";$password = "password";$dbname = "myDBPDO";

try {  $conn = new PDO("mysql:host=$servername;dbname=$dbname", $username, $password);

  $conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);  $stmt = $conn->prepare("SELECT id, firstname, lastname FROM MyGuests");

  $stmt->execute();

  // set the resulting array to associative  $result = $stmt->setFetchMode(PDO::FETCH_ASSOC);   foreach(new TableRows(new RecursiveArrayIterator($stmt->fetchAll())) as $k=>$v) {     echo $v;

  }} catch(PDOException $e) {  echo "Error: " . $e->getMessage();}$conn = null;echo "</table>";?>