ON DUPLICATE KEY UPDATE with WHERE - mysql

Question

I've got an INSERT ... ON DUPLICATE KEY UPDATE query and I am trying to add WHERE clause to it:
INSERT INTO `product_description` (
`product_id`,`language_id`,`name`,
`description`,`meta_description`,
`meta_keyword`,`tag`
) VALUES (
$getProductId, $languageId, '$pName', '$pDescription', '', '', ''
)
ON DUPLICATE KEY UPDATE
`name` = '$pName',
`description` = '$pDescription'
I want to restrict the UPDATE to those 2 conditions:
WHERE `model` = 'specific-model' AND `sku` NOT LIKE '%B15%'
If I add this part of query to the end of the original query I get a MySQL syntax error. What would be a working solution?
Update: Please note that model and sku are in another table, and the common key is product_id

Answer 1

I would suggest you to use some sort of prepared statement instead of concatenating strings, so you should do something like this:
INSERT INTO `product_description` (
`product_id`, `language_id`, `name`,
`description`, `meta_description`,
`meta_keyword`, `tag`
) VALUES (?, ?, ?, ?,'','','')
but this is not part of the question.
I was thinking of answering with a simple CASE WHEN but the challenging part of your question is that the restrict conditions are not in the product_description table but are from another table. So I think we can just use a TRIGGER:
CREATE TRIGGER product_description_upd
BEFORE UPDATE ON product_description
FOR EACH ROW
IF NOT EXISTS(SELECT * FROM models
WHERE product_id=new.product_id
AND model='Abc' AND `sku` NOT LIKE '%B15%') THEN
SET new.name=old.name;
SET new.description=old.description;
END IF;
//
then you can use an INSERT query like:
INSERT INTO `product_description` (col1, col2, ...)
VALUES (..., ..., ...)
ON DUPLICATE KEY
UPDATE name=VALUE(name),description=VALUE(description)
Please see a fiddle here.
The only thing to note here is that even a standard UPDATE query will be affected.

Answer 2

CREATE TABLE product_description (
product_id INT PRIMARY KEY,
name VARCHAR(100),
description VARCHAR(100)
);
CREATE TABLE models (
product_id INT,
model VARCHAR(100),
sku VARCHAR(100)
);
INSERT INTO models VALUES
(1, "Abc", "ZZZ"),
(2, "Abc", "B15");
INSERT INTO product_description VALUES
(1, "Car", "Red"),
(2, "Truck", "Pink");
INSERT INTO `product_description` VALUES (1, "NewCar", "DeepRed")
ON DUPLICATE KEY UPDATE name=VALUES(name), description=VALUES(description);
Assuming, product_id must be in models.
INSERT INTO `product_description` (product_id, name, description)
SELECT models.product_id, "SuperCar" as name, "DarkRed" as description
FROM `models` WHERE model="Abc" AND `sku` NOT LIKE "%B15%"
ON DUPLICATE KEY UPDATE name="UpdatedCar", description="UpdatedRed";
refer to http://sqlfiddle.com/#!9/69624e/1
Hopefully this solves the problem. You can play with SELECT query for different result.