Remove duplicate product with lower price using mysql query - mysql

Question

I have many duplicate products that I need to delete. Is there a query to delete these "Duplicates" with the "lower price" and/or "Same Price" an just keep 1 of each product?
The duplicates have duplicate "Product Name" I am using Opencart Version 2.1.0.1

Answer 1

Since you are using mysql, you need to use joins (partition by is not supported):
The select:
select p.*
from products as p
join
(
select name, min(price) as price
from products group by name having count(price) = 2
) as p2 on p2.name = p.name and p2.price = p.price;
Gets the lowest price for all duplicate products (where duplicate assumes there are exactly two rows of the same product).
To delete, change the initial select to a delete, as follows:
delete p.*
from products as p
join
(
select name, min(price) as price
from products group by name having count(price) = 2
) as p2 on p2.name = p.name and p2.price = p.price;

Answer 2

According to the schema on http://wiki.opencarthelp.com/doku.php?id=databse_schema and only one language the folowing query should solve your issue:
delete p1
from product p1
join product_description d1 on d1.product_id = p1.product_id
join product_description d2
on d2.product_id <> d1.product_id
and d2.language_id = d1.language_id
and d2.name = d1.name
join product p2 on p2.product_id = d2.product_id
where d1.language_id = 1 -- define the language used for product name
and (p2.price > p1.price -- delete if higher price exists
or p2.price = p1.price and p2.product_id < p1.product_id -- delete if same price with lower id exists
)
;

Answer 3

Without much info (which RDBMS, etc) I can only speculate this solution would work for you:
WITH Flagged AS
(
SELECT
ProductName,
CASE WHEN ROW_NUMBER() OVER(PARTITION BY ProductName ORDER BY Price DESC) = 1 THEN 0 ELSE 1 END AS Delete
FROM
Products
)
DELETE p
FROM Products p
JOIN Flagged f
ON (p.ProductName = f.ProductName)
WHERE f.Delete = 1;