Write query without join and using subquery - mysql

Question

I want to rewrite the join query with sub-query like IN(), ANY() operator.
Data set:
*categories*
categoryID name
5 ROD
7 CEMENT
*products*
productID categoryID name
7 5 BSRM 10mm
9 5 KSRM 5mm
10 5 Julius
11 7
12 5 BSRM 25mm
*sale_products*
saleID productID
118 9
119 9
120 9
121 9
122 12
123 12
124 12
This is my query to read saleID, product name and category name for which already have sold.
My query is:
SELECT sale_products.saleID, products.name, categories.name
FROM categories
INNER JOIN (products, sale_products)
ON categories.categoryID = products.categoryID
AND products.productID = sale_products.productID
Now I want to the result set without join and with the sub-query methodology.
I try in this way:
SELECT categories.name
FROM categories
WHERE categories.categoryID IN
(SELECT products.categoryID
FROM products
WHERE products.productID in
(SELECT sale_products.productID FROM sale_products))
this query only give me the category name but I need also saleID, product name.

Answer 1

Your original query looks queer. Why do you cross join products and sale_products?
It should better be:
select sp.saleid, p.name as product, c.name as category
from sale_products sp
join products p on p.productid = sp.productid
join categories c on c.categoryid = p.categoryid;
This is the straight-forward way to show the data. You can use subqueries instead, but I see no sense in it:
select
sp.saleid
(
select p.name
from products p
where p.productid = sp.productid
) as product,
(
select c.name
from categories c
where c.categoryid = p.categoryid
) as category
from sale_products sp;
Here is yet another query with subqueries. Again without any benefit over the simple query using direct joins on the tables.
select sp.saleid, p.name as product, c.name as category
from sale_products sp
join (select productid, name from products) p on p.productid = sp.productid
join (select categoryid, name from categories) c on c.categoryid = p.categoryid;