php - Check if an id exists in a table before adding it to another table -

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i'm doing small thing like feature see on facebook. way i'm doing this. have table called products contains products people can like. (stripped down):

id | prodname               | status (0=clear, 1=blocked) ---------------------------------------------------------- 1  | philips food processor | 0 2  | le sharp knife         | 0 3  | ye cool fridge         | 0  comes `likes` table this: id | prodname               | prodid | userid -------------------------------------------- 1  | philips food processor | 1      | 1 2  | le sharp knife         | 2      | 1 3  | ye cool fridge         | 3      | 1 4  | ye cool fridge         | 3      | 2

i need check, before adding likes table, if product id actually exists in products table , status = 0. lot of php code. way using sql? possible? using foreign keys or that?

i'm using innodb table type.

you can conditional insert. product 6 , user 7:

insert  likes         (prodname, prodid, userid) select  prodname ,       id ,       7    products   id = 6         , status = 0

if inserts no rows, know product did not exist status 0.


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