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author:php.cn  update time:2022-04-15 13:53:54

PHP MySQL reads data



Read data from MySQL database

The SELECT statement is used to read data from the data table:

SELECT column_name(s) FROM table_name

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

Related video tutorial recommendations: "mysql tutorial"http://www.php.cn/course/list/51.html

In the following example, we read the data of the id, firstname and lastname columns from the table MyGuests and display it on the page:

Example (MySQLi - Object-oriented)

<?php
$servername = "localhost";
$username = "username";
$password = 
"password";
$dbname = 
"myDB";
// 创建连接
$conn = new mysqli($servername, 
$username, $password, $dbname);
// 检测连接
if ($conn->connect_error) 
{
    die("连接失败: " . $conn->connect_error);
} 
$sql = "SELECT id, firstname, lastname FROM MyGuests";
$result 
= $conn->query($sql);
if ($result->num_rows > 0) {
    
// 输出每行数据
    while($row = $result->fetch_assoc()) 
{
        echo "<br> id: ". 
$row["id"]. " - Name: ". $row["firstname"]. " " . $row["lastname"];
    
}
} else {
    echo "0 个结果";
}
$conn->close();
?>
The following example reads all the records of the MyGuests table and displays them in the HTML table:

Instance (PDO)

<?php
echo "<table style='border: solid 1px black;'>";
echo "<tr><th>Id</th><th>Firstname</th><th>Lastname</th><th>Email</th><th>Reg 
date</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 * FROM MyGuests"); 
    $stmt->execute();
    // 设置结果集为关联数组
    
$result = $stmt->setFetchMode(PDO::FETCH_ASSOC); 
    
foreach(new TableRows(new RecursiveArrayIterator($stmt->fetchAll())) as 
$k=>$v) { 
        echo $v;
    
}
    $dsn = null;
 }
catch(PDOException 
$e)
{
    echo "Error: " . $e->getMessage();
}
$conn = null;
echo "</table>";
?>

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