 So, one more query I want to make is now we're dealing with, obviously, medical information, which means we're dealing with medical bills, and occasionally, guess what, there are going to be people who do not pay their medical bills. So what I want to go ahead and do is I'm going to go ahead and let's take a look at that invoice table. You see that, again, every invoice has an associated visit to it, and every visit has a patient to it. So I can immediately find out who owes what. Well, we also see that my invoice table has an amount, a reason, and whether or not they are paid. So what I'm going to go ahead and do is anyone who has not paid, I'm going to just go ahead and apply a late fee to them. I know, future, just work with it. So I come in here, and I'm going to go to my query design. Now, again, I'm going to first add in my invoice, and then I'm going to add in my patient information. Now, you see that there's not too much of a link going on there, but when I add in the visit table, the visit table acts as that bridge between these two. I cannot have an invoice without a visit. I can't have a visit without a person, a patient. So the first thing I'm going to say is I want to look up my first and last name of my patient. Again, boom, I get that pretty easily. But then I want to go ahead and get the invoice date, the item, the amount, and whether or not they paid. So again, now if I run this, what I should see is when they were invoiced for this amount, for what they're invoiced for an office visit, here's the amount, invoice paid. Again, I don't really care if they've paid. I got my money. I need the ones that haven't paid up and I need to go and convince them to. So to kind of make a query for a Boolean yes or no statement, yes or no. Now it's going to try and say now, don't worry about that. You can hit escape and it'll vanish. Now when I run this, all of a sudden invoice paid, only my nose are going to show up pretty nice. That's exactly what I want. So you can see Julia Ingram hasn't paid $250. I haven't paid $125. Now just like when we were dealing with Hartford, because I know these people haven't paid, I don't need to show that. I can uncheck that. Now I'm going to go ahead and save this as applying, applied late fees. Now that I've built this out, how do I apply a late fee? How do I calculate a late fee? Let's say I'm going to give them a 5% late fee. Well what I can do is I can actually come up here and you notice I have this query setup section and I can actually click on the builder option. The builder option is actually going to bring up this dialogue box which allows me to do sort of a mathematical calculation. Invoice AMT, invoice AMT is currency, it's money, it's an amount. So I can actually select it and then I can come in here and I can say times 0.05. We apply a 5% late fee and when I hit OK, that's going to appear right here. Now I run this. You'll see that I get exactly that. I get 250 and then this 12.5. All right, well that's not really useful. Well if we look at that design, notice what it says right there, X E P R 1. That's actually a way for me to give a caption to a sort of calculated field. This field doesn't exist anywhere in my database except for in this query. And so I can go ahead and just apply late fee. Oh, where'd you go? All right, I'm not sure what happened there. So I'll just do it again, late fee. Okay, there we are. When I run it, now I see late fee. Now again, I want to keep on dulling this up a little bit because we're dealing with currency, we're not dealing with arbitrary numbers. To do that, with this selected or highlighted, I want to go to my property sheet. This property sheet option is going to build up just another little extra thing. And as you can see, I get a few different options. I can change the format from just nothing to currency. And I can change my decimal places from nothing to two. Now when I run this, you can see that I have applied that. So I get now invoice amount, late fee. So the last thing I'm going to do is, again, I'm dealing with my invoice amount. I'm dealing with my late fee. Let's merge these together. Let's actually kind of add these together. So I'm going to add in another field. Again, notice I have invoice amount. Well, first I'm going to say new balance because we're dealing with a new balance. That's going to be my caption again. In invoice amount plus late fee. We run this, contains invalid syntax. There we are. Now just because I saw that, okay, what did I do there? Builder. It was new balance. If you see that EXPR, just go ahead and get rid of that plus late fee, okay? That gives me that new balance. When I run this, you see I get my invoice amount, I get my late fee and then I get my new balance as well. So I see a new calculated total for every one of my unpaid invoices.