Question

I am making a product database for my website. I currently have:

Products Table: Product ID, Product name, Price

Product_meta Table: Pmeta_id, Product ID, metaKey, metaValue

I basically want it so I can query a product by specifying the meta key and either put a key=>value pair to it, or get the value by the key.

I believe WordPress has a similar approach but am not quite sure how to go about making the functions to get the data. I assume it will involve table joins???

Any help would be appreciated.

Answer 1

SELECT * FROM Product_meta AS M
LEFT OUTER JOIN Products AS P ON ( P.Product_ID = M.Product_ID )
WHERE M.metaKey = ...

Or turn it around if the Products table is leading:

SELECT * FROM Products AS P
LEFT OUTER JOIN Product_meta AS M ON ( P.Product_ID = M.Product_ID )
WHERE M.metaKey = ...

You can also change LEFT OUTER JOIN to INNER JOIN when you only want to display the records that are both in the Products table and in the Product_meta table

If you want to have more than one value in the WHERE clause then use this query:

... WHERE M.metaKey IN (..,..,..)

Make sure your data is comma seperated