WEBVTT 00:07.520 --> 00:08.120 Alrighty. 00:08.150 --> 00:13.520 So let's go ahead and learn about a group by clause in PostgreSQL. 00:14.120 --> 00:14.570 All right. 00:14.570 --> 00:15.740 Let me go ahead and see. 00:15.980 --> 00:20.180 We have these countries and I have these strings. 00:20.180 --> 00:23.690 And each of these students are from different countries. 00:23.690 --> 00:28.820 And now I want to know how many students have come from each of these countries. 00:28.970 --> 00:29.810 Remnants. 00:29.840 --> 00:32.840 China Russia Thailand appeared numerous times. 00:32.870 --> 00:34.220 What I want. 00:34.250 --> 00:39.170 How many of these students that come from each of these countries. 00:39.890 --> 00:42.650 So how can we be able to do that? 00:43.130 --> 00:45.170 So if I say we should do that. 00:45.440 --> 00:46.640 So let me go ahead and see. 00:46.670 --> 00:47.150 All right. 00:47.180 --> 00:49.220 Select all from students. 00:49.220 --> 00:54.860 And uh, in warhead I use the group by clause. 00:54.860 --> 00:58.640 And in order to use that you might go ahead and see. 00:58.700 --> 01:05.310 Let's go ahead and select and uh Country from. 01:07.320 --> 01:08.100 Students. 01:08.100 --> 01:09.210 Then. 01:10.470 --> 01:11.430 Group. 01:14.610 --> 01:17.700 Group by then country. 01:17.850 --> 01:20.100 And then let's go ahead and query. 01:20.130 --> 01:28.350 Then we have this Bangladesh Indonesia Venezuela Cameroon and so on. 01:29.190 --> 01:32.040 So that is more than 24 out of 24. 01:32.070 --> 01:34.170 But one of those group is countries. 01:34.170 --> 01:36.600 What I want to have a count. 01:36.600 --> 01:43.170 That means I want to see Bangladesh number of displays then Indonesia number of distilleries. 01:43.200 --> 01:45.120 How can we be able to do that. 01:45.120 --> 01:53.520 So in order to do that, if you want to use a group by clause, we go ahead and use what is called count. 01:53.520 --> 02:01.200 In order to use count, what you need to do is you go ahead and say select from a select country. 02:01.200 --> 02:07.090 And then you put a comma and then add counts. 02:09.430 --> 02:16.390 So this counts is when we have us to determine how many of these students. 02:16.390 --> 02:18.160 And we're going to count all. 02:18.190 --> 02:20.290 Then we'll go ahead and execute this. 02:20.320 --> 02:22.450 Now we have Bangladesh. 02:22.450 --> 02:24.850 Count is five students. 02:24.880 --> 02:27.490 Indonesia is a one on one. 02:27.520 --> 02:30.730 That is a very large number of people. 02:30.730 --> 02:39.640 And uh, you can see down there, you can still have so many of them and uh, Poland, Somalia one, 02:39.670 --> 02:43.660 Haiti two, Costa Rica three, and so on. 02:44.350 --> 02:50.140 Now we can also go ahead and uh, we have one of the largest right in here as China. 02:50.140 --> 02:50.890 We have one, right. 02:51.040 --> 02:52.180 It's a one. 02:52.360 --> 02:57.190 It's nine people from China, over 101 from Indonesia. 02:57.370 --> 03:04.870 Now you go ahead and, uh, ordered this alphabetically and to order this alphabetically because I've 03:04.870 --> 03:05.950 learned how to do that. 03:05.980 --> 03:07.920 What I need to do is go quiet. 03:07.950 --> 03:11.370 I used the other class and I'm going to say order. 03:12.120 --> 03:13.950 By then. 03:13.980 --> 03:14.880 You will see. 03:17.100 --> 03:18.120 The country. 03:18.210 --> 03:21.990 And then we go ahead and execute this query. 03:22.110 --> 03:33.840 And now we have our Afghanistan six Albania five, America, Samoa one, Argentina 16 and down to the 03:33.840 --> 03:37.110 last one, which is Yemen, and that is six. 03:37.110 --> 03:38.640 Vietnam is 11. 03:39.750 --> 03:40.080 All right. 03:40.140 --> 03:44.310 So this is how we use the group by clause in PostgreSQL. 03:44.310 --> 03:46.890 So go ahead and use that group that check it out. 03:46.890 --> 03:49.980 And you really love what you're doing on the here. 03:50.010 --> 03:51.630 So practice with this. 03:51.660 --> 03:55.980 If you have any question under this Moorhead and use the question and answer section. 03:55.980 --> 03:58.830 And I'm going to get back to you as soon as possible. 03:58.830 --> 04:00.450 So thank you so much. 04:00.450 --> 04:04.020 And I'm going to see you in the next video lecture.