如何使用另一个查询的结果获取查询数据？

Question

i wanted to get the data from my second query using the first query result. But i cant What i wanted is to get id from the first query and get content using the id i got.

My 1st query

$query = "SELECT book_id , title, SUM(quantity) AS total_sales FROM  shopping_cart GROUP BY title ORDER BY total_sales DESC ";

$result = mysqli_query($link, $query) or die(mysqli_error($link));

                            $row = mysqli_fetch_array($result);

2nd query

for ($rcount = 0; $rcount < count($row); $rcount++) {
                                $wanted_id = $result[$rcount]['book_id'];
                                $query1 = "SELECT * FROM books where id ='$wanted_id' ";
                                $result1 = mysqli_query($link, $query) or die(mysqli_error($link));
                            }

i know theres somethign wrong with it but right now i cant seem to figure what how do i do it was wondering if im suppouse to use nested queries.

EDIT: heres my nested query

$query = "SELECT * from books where id IN (SELECT book_id AS id, title, SUM(quantity) AS total_sales FROM  shopping_cart GROUP BY title ORDER BY total_sales DESC )";

i got a "operand should contain 1 column error" tho

Answer 1

You only need one query, join the books table to your shopping cart table to get the info about each book.

SELECT
  books.*,
  shopping_cart.book_id,
  shopping_cart.title,
  SUM(shopping_cart.quantity) AS total_sales
FROM
  shopping_cart
INNER JOIN
  books
ON
  shopping_cart.book_id = books.id
GROUP BY
  shopping_cart.title
ORDER BY
  total_sales DESC