无法选择3个用户ID相同的表。 没有错误出现

Question

So I have 3 tables like so

Table: users
    user_id(int)   |  phone(int)

Table: products
    prod_id(int)   |  prod_info(varchar)

Table: prod_owners
    owner_id(int)  |  user_id  |  prod_id

I created a function where I can parse in a phone number. It will look up that phone number to get the user_id. The using the user_id it will join the prod_owners table. Then using the prod_id from the prod_owners table, it will join the products table, where the user_id has the same phone number we parsed in.

However, when I run the function, I get no errors, or anything. Its just blank. I know the function works because when I do SELECT * FROM users. It works. I also know there is data with in the table (the data I want it to output).

function get_info($stmt, $phone) {

    $userID = search_user($stmt, $phone); // I feel I don't even need this
                                        // I feel I can put this in the
                                        // sql statement itself. But I am
                                        // unsure how
    if ($userID == false) {
        return "Sorry, user not found";
    }

    $sql = "SELECT u.user_id, o.prod_info 
            FROM users u 
            JOIN prod_owners o 
              USING user_id 
            JOIN products 
              USING o.prod_id 
            WHERE u.phone = ?";
    if(!mysqli_stmt_prepare($stmt, $sql)) {
        return false;
    } else {
        mysqli_stmt_bind_param($stmt, "i", $userID);
        mysqli_stmt_execute($stmt);
        $result = mysqli_stmt_get_result($stmt);
        while($row = mysqli_fetch_assoc($result)) {
          echo $row['prod_info'] . "<br>";
        }
    }
}

Answer 1

Try this query, It should must help you.

SELECT users.user_id, products.prod_info FROM users u 
            INNER JOIN prod_owners ON prod_owners.user_id  =  users.user_id
            INNER JOIN products ON products.prod_id  =  prod_owners.prod_id