How can the "No database selected" error be resolved when using PHP and MySQL?

The "No database selected" error occurs when a database is not specified in the connection to MySQL in PHP. To resolve this issue, you need to explicitly select the database after establishing the connection using the mysqli_select_db() function. 

// Establish connection
$conn = mysqli_connect("localhost", "username", "password");

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

// Select the database
$db_selected = mysqli_select_db($conn, "database_name");

if (!$db_selected) {
    die ("Database selection failed: " . mysqli_error($conn));
}

Keywords

PHP MySQL database error handling mysqli_connect

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