Question

In a PHP function, sometimes I find that something can be echoed, yet it cannot be returned.

For example, this sucessfully echo’s the result onto the page:

function get_page_id( $path ) {

global $mysqli;
if ($stmt = $mysqli->prepare("SELECT state FROM country WHERE city = ?")) {
    $stmt->bind_param("s", $city);
    $stmt->execute();
    $stmt->bind_result($state);
    $stmt->fetch();
    $stmt->close();
    echo $state;
}

}

However, this function does not return the value:

function get_page_id( $path ) {

global $mysqli;
if ($stmt = $mysqli->prepare("SELECT state FROM country WHERE city = ?")) {
    $stmt->bind_param("s", $city);
    $stmt->execute();
    $stmt->bind_result($state);
    $stmt->fetch();
    $stmt->close();
    return $state;
}

}

What makes a value able to be echoed but not returned?

$state variable is called elsewhere and is included as a global but is not included in the example. What is interesting is that when I change the function to return $state.”; it returns the result as I would expect it to, but only when I append the empty string does it do this. Why could that be?

Answer 1

However, this function does not return the value: I cannot reproduce that behaviour

e.g.

<?php
$mysqli = new mysqli('localhost', 'localonly', 'localonly', 'test');
if ($mysqli->connect_error) {
    die('Connect Error (' . $mysqli->connect_errno . ') ' . $mysqli->connect_error);
}
setup($mysqli);

$state = get_page_id('acity');
echo 'state: ', $state;

function get_page_id( $city ) {
    global $mysqli;
    if ($stmt = $mysqli->prepare("SELECT state FROM tmp_country WHERE city = ?")) {
        $stmt->bind_param("s", $city);
        $stmt->execute();
        $stmt->bind_result($state);
        $stmt->fetch();
        $stmt->close();
        return $state;
    }
}


function setup($mysqli) {
    $mysqli->query('
        CREATE TEMPORARY TABLE tmp_country (
            id int auto_increment,
            city varchar(32),
            state varchar(32),
            primary key(id),
            unique key(city)
        )
    ') or die($mysqli->error);
    $mysqli->query("INSERT INTO tmp_country (city,state) VALUES ('acity','astate'),('bcity','bstate')") or die($mysqli->error);
}

prints state: astate on my machine as expected.