MySql Update if if exists如果不存在则插入

Question

I'm trying to insert new to the table or to update the previous one in the same query.I can solve it with a bit of php code but my goal is to make it all in sql.

The problem

My app has names in different languages, I can add new languages to it.When i add new languages the translations for my products raise. My goal is to send the script information ,and if two columns are same than the data should be updated, but if they are not they should be updated.

Here is some of my query:

"INSERT INTO product_name(link,product_id,language)
VALUES(:link,:product_id,:language) ON DUPLICATE KEY UPDATE
link=:link,product_id=:product_id,language=:language"

This query above solves one portion of the problem, but when i want to change the link it adds new data.My goal is to change the link ,and if the product_id and language are same in that row than it should be updated,if not than a new one shall be added.Unique wont solve the problem since i need to use same languages and id's in the table.

Answer 1

I think you just need a unique constraint on (product_id, language) -- and no unique constraint or primary key on all three columns.

CREATE UNIQUE INDEX unq_productname_product_language ON product_name(product_id, language);

This requires that the pair of values be unique, not each one individually.

Then this should do what you want:

INSERT INTO product_name(link, product_id, language)
    VALUES (:link, :product_id, :language)
    ON DUPLICATE KEY UPDATE link = VALUES(link);

Notice that this version uses VALUES(link) . This uses the value being inserted in the statement. I think that is clearer than repeating the expression.