PHP：迭代另一个函数和输出结果的函数

Seems like this would be pretty simple, however, I'm running into an issue:

Here's the code:

function getValidCustomers() {
    global $db;
    $getCustomers = $db->GetAll("SELECT * from customers where CustomerActive='1' AND protected IS NULL or protected=0;");
    foreach($getCustomers as $customer) {
        echo $customer['CustomerID']."
";
    }
}

function updateValidCustomers() {
    $customers = getValidCustomers();
    for ($i = 0; $i < sizeof($customers); $i++) {
        echo "DEBUG: $customers[$i]
";
    }
}

updateValidCustomers();

Basically, the output right now is a list of the CustomerIDs (from updateValidCustomers()). I just want updateValidCustomers() to get the data from getValidCustomers() and then loop through it, so that I can run another query on it that will actually manipulate the database.

Any ideas?

getValidCustomers doesn't return anything, maybe you mean this:

function getValidCustomers() {
    global $db;
    $getCustomers = $db->GetAll("SELECT * from customers where CustomerActive='1' AND protected IS NULL or protected=0;");
    foreach($getCustomers as $customer) {
        echo $customer['CustomerID']."
";
    }
    return $getCustomers;
}

Add return $getCustomers; to getValidCustomers() :D

getValidCustomers() doesn't return anything - it just echoes

Add return $getCustomers to the end of getValidCustomers()