MySQL查询的MySQL和PHP问题

Question

I'm currently having a problem getting a variable to display in a php echo statement, and I don't know whats going wrong. This is the line I'm concerned about:
$query="select password from ouser where pkey=".odb_get_pkey($user);

Is there anything wrong with this line?
Here is my code in context:

function odb_get_pkey($username)
{
    $db=odb_connect();
    echo "Get the primary key".oLF();
    $query="select pkey from ouser where username='$username'";
    $pkey=odb_get_field($query,$db);
    echo $pkey.oLF();
}


function odb_get_password($user)
{
    $db=odb_connect();
    echo "Get the password".oLF();
    $query="select password from ouser where pkey=".odb_get_pkey($user);
    echo $query;
    $password=odb_get_field($query,$db);
    echo $password.oLF();
}


function odb_get_field($query,$db)
{
    $result = mysqli_query($db,$query);
    $row = mysqli_fetch_row($result);
    return($row[0]);
}

Currently I am just calling the odb_get_password function which will call the other two functions, and I just get the query select password from ouser where pkey= , and nothing after the equals sign. I don't know php or MySQL very well. Not sure what I'm doing wrong. Thank you for any help!!

Answer 1

You never return the function value for odb_get_pkey . As you might know, echo prints the given variable to the page, while return returns it from a function. That explains why the $query variable has no value added to it in the end.