MySQL Retrieve repeatin results using "in" condition - php

Question

Of all aspects of coding, SQL is my weakest skill, so please forgive me if I sound like I don't know what I'm talking about, because I probably don't!
Situation:
Building a shopping cart where the table named "cart" has a field named "products" of type VARCHAR 255, and the value of "products" will be a comma delimited string. Each element of the string will be a number which represents the id of a product from the "products" table.
A customer's record may contain a value in the "products" field that looks like 1,1,1,2,3. This would mean the customer has added three of item 1, one of item 2, and one of item 3.
Problem:
So, here is the sql statement I have presently, but the problem is I need a sql statement that will return repeat product data from the product table:
SELECT product_id, product_name,price
FROM products
WHERE id in ('1','1','1','2','3')
The result of that will be a set of three items from the "products" table, 1 and 2 and 3. In other words, it doesn't give me the product data for the three '1's, it only gives me a distinct value. Not 3 values from the products table, but 5 values from the products table, where the first three results are identical, because they are the same product_id=1.
I need a sql statement that will give me the redundant product information, because after all, a person can order three widgets with the product_id = 1.
cart:
id INT(15)
uid VARCHAR(32)
email VARCHAR(100)
products VARCHAR(255)
date DATETIME
checkout TINYINT(1)
products:
id INT(15)
product_id varchar(32)
product_name varchar(128)
product_associations varchar(255)
short_description varchar(255)
long_description mediumtext
price varchar(32)
image varchar(128)
My php code:
$productslist = str_replace(",","','",$row->products);
$productslist = "'" . $productslist . "'"; echo $productslist;
$sql2 = "SELECT product_id, product_name,price FROM products WHERE id in ($productslist)";
$query2 = $this->db->query($sql2);
$i = 0;
if ($query2->num_rows() > 0){
foreach ($query2->result() as $row2){
$products[$i]['product_id'] = $row2->product_id;
$products[$i]['product_name'] = $row2->product_name;
$products[$i]['price'] = $row2->price;
$i++;
}
}
...and a result of this query would be:
Product ID: #0001
Product Name: "Ducky"
Price: $1.50
Product ID: #0002
Product Name: "Horse"
Price: $1499.00
Product ID: #0003
Product Name: "T-shirt"
Price: $5.00
Update:
In the interest of best practices, I studied the "normalized" table theory, then rolled back the above scheme of a comma-delimited products field. I created a separate table called "cart_list", with the fields:
id
cart_id
product_id
...and I simply insert new records for each new "add to cart", keyed to the cart table by the cart_id field, and keyed to the product data through the product_id field.

Answer 1

a bit ugly but that would do the trick:
create temporary table t (id integer);
insert into t(id) values (1),(1),(2),(2),(3);
select product_id, product_name,price from t inner join products where t.id = products.id;
drop table t;