Now, this is where the fun begins.
So what I'm going to start doing is
I'm going to show you the slide, and I'm
going to switch to the VM and do some demoing.
So when you have two tables in a database-- here,
we have the messages, and in this one,
the attachments are in a different.
So we have something called video.
You may have something else called image, audio.
But you have to find what's in common.
So when we wrote our queries on Day 1,
we simply said, select these columns from this table--
easy enough.
Now, we have to say, select these columns from this table,
but also bring this table in, and show me these columns.
So to do that, you have to find what they have in common.
So here, we can see we have something called _video_id.
The first thing you should do is scan for a table called video.
We got lucky.
And guess what--
ID.
So this is literally telling you message dot video
ID equals video ID.
Great.
Now, you can do whatever you want.
We could say, we want key, we want path,
we want all these things.