无法用php将数据插入mysql

Question

ok so I can connect and view the database with my php code, however I can not insert data into it.here is the query I tested with phpmyadmin which was able insert new data into my table

INSERT INTO `members` ( `id` , `username` , `email` ) 
VALUES ( 123456789, 'russi', '[e-mail]' )

then I tried to put it into my actual php file

<?php
$servername = "localhost";
$username = "root";
$password = "blablabla";
$dbname = "test_database";

// Create connection
$conn = new mysqli($servername, $username, $password, $dbname);
// Check connection
if ($conn->connect_error) {
    die("Connection failed: " . $conn->connect_error);
}
$sql = "INSERT INTO 'members' ('id', 'username', 'email')
VALUES (2339978, 'vladtheimpalor', '[e-mail]')";
$sql = "SELECT id, username, email FROM members";
$result = $conn->query($sql);

if ($result->num_rows > 0) {
    // output data of each row
    while($row = $result->fetch_assoc()) {
        echo "id: " . $row["id"]. " - username: " . $row["username"]. " -email:" . $row["email"]. "<br>";
    }
} else {
    echo "0 results";
}
$conn->close();
?>

so select function works but insert does not.

Answer 1

You are overriding your $sql variable w/o executing it. Besides that you should not use single quotes for columns, but backticks (see When to use single quotes, double quotes, and backticks in MySQL)

Change

$sql = "INSERT INTO 'members' ('id', 'username', 'email')
VALUES (2339978, 'vladtheimpalor', '[e-mail]')";
$sql = "SELECT id, username, email FROM members";
$result = $conn->query($sql);

to

$sql = "INSERT INTO `members` (`id`, `username`, `email`)
VALUES (2339978, 'vladtheimpalor', '[e-mail]')";
$result = $conn->query($sql);
$sql = "SELECT id, username, email FROM members";
$result = $conn->query($sql);