WEBVTT 00:03.660 --> 00:08.180 So in this section we're going to focus on what are called logical operators. 00:08.250 --> 00:13.530 Actually we're focusing on operators in general and most of the ones we're going to work with are logical 00:13.530 --> 00:15.660 operators that distinction doesn't really matter though. 00:15.780 --> 00:22.770 I'm just going to call them all logical operators and they allow us to add logic into our sequence statements. 00:22.770 --> 00:26.760 So up until this point we've seen things like well like what. 00:26.910 --> 00:33.810 Which allows us to select things based off of you know text looking or containing certain strings matching 00:33.810 --> 00:34.890 patterns. 00:34.890 --> 00:40.590 We've seen how to do things where we can check you know select all books where the title is exact the 00:41.250 --> 00:45.750 Lincoln and the Bardo or where a released year is exactly 2013. 00:45.750 --> 00:50.940 But there's a whole slew of other things that we'd like to be able to select based off of. 00:51.210 --> 00:53.330 And that's what we're going to focus on in this section. 00:53.550 --> 00:59.050 So we're going to see how to do things like select all books not published in 2017. 00:59.370 --> 01:01.150 Right now we don't have a way of doing that. 01:02.460 --> 01:06.880 Or what about select all birthdays between two different dates. 01:06.960 --> 01:14.510 So not just all birthdays that are exactly you know April 22nd 1990 or 1992 or whatever it is. 01:14.610 --> 01:24.370 But between those two dates or select all items so this is some table I made up called items all items 01:24.370 --> 01:28.310 that are in stock and price below 1999. 01:28.330 --> 01:29.800 So that's two different things. 01:29.830 --> 01:32.090 We know how to select all items that are in stock. 01:32.290 --> 01:37.360 But there's a second component which is not only the need to be in stock but they need to be priced 01:37.360 --> 01:38.910 below 1999. 01:39.130 --> 01:41.720 And right now we don't know how to do that either. 01:41.830 --> 01:46.730 With that lengthy introduction out of the way let's take a look at some of our first ones. 01:46.810 --> 01:50.850 So the actual first one we're going to look at is called not equal. 01:50.850 --> 01:55.080 And it looks like this exclamation point and an equal sign. 01:55.510 --> 01:58.170 So we've seen hundreds of things using equal sign. 01:58.180 --> 01:58.480 Right. 01:58.480 --> 02:09.220 We've done you know select let's do title released here from books where Let's do release year so we're 02:09.260 --> 02:12.890 released here is exactly 2017. 02:13.840 --> 02:16.710 So we've seen how to do this you know with equal sign. 02:16.960 --> 02:18.250 We've been doing it all the time. 02:18.410 --> 02:21.610 However what if I want to do the opposite. 02:21.610 --> 02:26.340 I want all books that were released in any year excluding 2017. 02:26.680 --> 02:32.470 So what we want to do is basically replace that equal sign with a not equals. 02:32.650 --> 02:33.820 So we could do that. 02:34.040 --> 02:40.720 So like title from books where a year is not equal to 2017 if you're familiar with any programming languages 02:41.020 --> 02:43.630 you've probably come across this not equals. 02:43.720 --> 02:46.920 It's a pretty universal way of writing not equals. 02:47.020 --> 02:49.690 So let's give it a shot. 02:49.720 --> 02:54.500 Recall this and just replace it with not equals. 02:54.620 --> 03:01.610 And now you can hopefully see that we get everything back except for Lincoln and the bardo. 03:01.880 --> 03:07.430 And of course if there is more than one book released in 2017 then we would get any book back or all 03:07.430 --> 03:13.970 books back except that those books from 2017 so we can see that it's gone. 03:14.090 --> 03:21.080 We could do the same thing but instead of working with this year what if we do it with author. 03:21.170 --> 03:24.030 So let me just start over here. 03:24.050 --> 03:32.310 Let's select the title and author last name from books and we'll start just with all of them. 03:34.340 --> 03:41.560 And then let's select where author last name is exactly equal to Harris. 03:41.770 --> 03:54.010 So we have two Harris's where author name equals Harris just like that and we get those too. 03:54.500 --> 03:57.170 And by just flipping the switch here. 03:57.500 --> 04:02.870 That exclamation point we now get everything except those two. 04:03.280 --> 04:03.590 OK. 04:03.620 --> 04:05.140 So hopefully you get the point by now. 04:05.300 --> 04:11.440 Not equals works like you would expect if you're not familiar with the exclamation point. 04:11.450 --> 04:16.340 It might take a little bit of getting used to but otherwise it's pretty straightforward. 04:16.340 --> 04:18.890 It's the opposite of equals awesome. 04:18.920 --> 04:22.050 So that's the first one that we're taking a look at but we have quite a few more. 04:22.070 --> 04:26.090 Next up we're going to talk about something very similar which is not like.