How to delete a certain row from mysql table with same column values?

Question

I have a problem with my queries in MySQL. My table has 4 columns and it looks something like this:

id_users    id_product    quantity    date
 1                     


        

Answer 1

There are already answers for Deleting row by LIMIT. Ideally you should have primary key in your table. But if there is not.

I will give other ways:

1. By creating Unique index

I see id_users and id_product should be unique in your example.

ALTER IGNORE TABLE orders ADD UNIQUE INDEX unique_columns_index (id_users, id_product)

These will delete duplicate rows with same data.

But if you still get an error, even if you use IGNORE clause, try this:

ALTER TABLE orders ENGINE MyISAM;
ALTER IGNORE TABLE orders ADD UNIQUE INDEX unique_columns_index (id_users, id_product)
ALTER TABLE orders ENGINE InnoDB; 

2. By creating table again

If there are multiple rows who have duplicate values, then you can also recreate table

RENAME TABLE `orders` TO `orders2`;

CREATE TABLE `orders` 
SELECT * FROM `orders2` GROUP BY id_users, id_product;