php发出返回查询

So I have my query in which I am trying to get the "password" field to return because I am having issues with my login:

$res = $db->query("SELECT `password` FROM users WHERE username = 'joeybab3'");

and I get the error :

"object of class mysql_result cannot be converted to a string"

So some googling got me this:

list($res) = $res->fetch_row;

but that just returns blank when I use echo.

mysqli::query method returns a mysqli_result object. It is an object, that's why you cannot use echo to print it out.

You need to use fetch_array/fetch_assoc/fetch_row methods to really get the data out of it.

In this case, you could use:

$row = $res->fetch_assoc(); 
$password = $row['password'];
echo $password;

fetch_row is a function, calling it like this should work.

list($res) = $res->fetch_row();

Edit:

Looks like you're using the MySQL library which has been deprecated. You should choose a different api if possible.

Then use this code:

$sql = "SELECT 'password' FROM users WHERE username = 'joeybab3'";

and echo $sql.

This is how I would do it.