Question

I really need some help with some SQL.

Question 1:

It’s easy enough to get all “assets” that belong to a “presentation” if the asset has a corresponding “presentationid” within it’s table.

SELECT * FROM asset WHERE presentationid = 3

But how to I accomplish the same thing by joining? What’s the best way to say:

SELECT * FROM asset WHERE ... asset is connected to presentation via “presentationasset”:

TABLE asset
id
name

TABLE presentation
id
name

TABLE presenationasset
id
presentationid
assetid

I hope this makes sense. I want to list out all of the actual assets and their columns, not the association table. 🙂

Question 2: (not as important)

I have my application setup so that “presentation” is a class and “asset” is a class…

With question 1 in mind, how do I return each of the associated assets as “asset” objects? Or does that even matter?

Answer 1

Q1:

SELECT a.id, a.name
FROM asset a 
JOIN presentationasset pa ON pa.assetid = a.id AND pa.presentationid = 3
JOIN presentation p ON p.id = pa.presentationid