WEBVTT 00:07.700 --> 00:10.460 I welcome you back again to the virtual PostgreSQL. 00:10.460 --> 00:14.090 And here let's go ahead and learn about the keyword distinct. 00:14.420 --> 00:15.950 So what's the first thing like. 00:15.950 --> 00:16.730 What is distinct. 00:16.730 --> 00:22.820 And it's very important aspect in PostgreSQL or in SQL queries. 00:23.270 --> 00:30.950 Now you might have things like uh, let me say I want to select, uh, let me go ahead and select oh. 00:33.650 --> 00:40.040 I want to select, uh, all brown students or let me go ahead and select country. 00:42.350 --> 00:46.550 I want to start country from students. 00:47.450 --> 00:53.810 And if I go over here you can see I have a Russia, I have China, Russia, Thailand. 00:53.840 --> 01:02.090 And uh, if you go down here, you can see I have Indonesia and I have Indonesia, and I have Philippines, 01:02.120 --> 01:04.220 I have Philippines and Philippines. 01:04.250 --> 01:10.520 Now, remember, if you go down on this, you can continue to open up all this. 01:10.550 --> 01:11.000 What? 01:11.030 --> 01:13.610 I really love working over here. 01:14.450 --> 01:17.810 So if I go ahead and select country over here. 01:17.840 --> 01:21.230 Go ahead and select country and load this year. 01:21.260 --> 01:22.670 I have all this. 01:22.700 --> 01:27.740 And I can select most of these numbers for which most times I have China and I have China. 01:28.010 --> 01:32.300 And now I just want to select I want some of the countries that are here. 01:32.330 --> 01:34.490 I just want to know them by one. 01:34.520 --> 01:40.310 Like say China, then Poland, Indonesia, Philippines, Bulgaria, whatever. 01:41.060 --> 01:41.510 Again. 01:41.540 --> 01:47.570 Then Portuguese without repeating China, uh Philippines and uh, Czech Republic. 01:47.600 --> 01:50.120 So how can I be able to do that? 01:50.150 --> 02:03.050 So if I go ahead and say select a country from students and, uh, I see order, order by the country 02:04.280 --> 02:12.230 with a semicolon at the end and run this thing, you can see that this actually arranged this from Afghanistan 02:12.260 --> 02:16.070 down to Albania, Argentina. 02:16.070 --> 02:19.950 And if I scroll this down, let's go ahead and check it out. 02:19.950 --> 02:21.930 And I have Yemen. 02:21.960 --> 02:24.210 I have total of 1000 rules. 02:24.210 --> 02:28.200 And consider Yemen repeated many times and Vietnam repeated many times. 02:28.230 --> 02:33.930 Yes, because these are assigned to some of these rules or all of the rules. 02:33.930 --> 02:35.970 But I just want to know only. 02:36.000 --> 02:41.970 I just want to know the numbers of the countries and the distinct numbers and the countries that are 02:42.540 --> 02:44.370 inside this data set. 02:44.400 --> 02:53.310 So the way to do that is, uh, by using that keyword distinct, and I want to use the keyword distinct. 02:53.340 --> 02:55.980 All I need to do is I have to say select. 02:55.980 --> 03:00.450 And then I'll go ahead and insert distinct. 03:00.810 --> 03:09.780 So if I should put those distinct country, it means I want to select just one out of control repeated. 03:09.780 --> 03:15.780 Just one out of the countries are repeated to show the countries that are all in here. 03:15.780 --> 03:17.760 And if I run this query let's check it out. 03:17.790 --> 03:22.860 You can see you have Afghanistan, just one Albania, one American Samoa. 03:22.890 --> 03:24.900 Samoa or Angola? 03:24.930 --> 03:25.890 Argentina. 03:25.920 --> 03:29.130 Armenia, Australia and so on. 03:29.130 --> 03:39.390 And if I should go right down here, I have Yemen and Vietnam and have a row of modern 24 of 124 and 03:39.390 --> 03:48.390 something is applicable to, let me say first underscore name. 03:48.390 --> 03:52.140 And if you select that from first underscore name. 03:52.200 --> 03:55.890 And when I say first underscore name. 03:55.890 --> 04:04.800 And if I run this first and check it out, you see we have rules of 941 instead of 1000, because there 04:04.800 --> 04:07.020 are names that are actually repeated by the Serbs. 04:07.020 --> 04:09.810 And that is applicable to all of these. 04:09.810 --> 04:12.990 And you can also arrange these in alphabetical order. 04:14.370 --> 04:16.950 So this actually starting from alphabetical order. 04:16.950 --> 04:23.130 And if you want that to start from descending order, all I need to do is I'll go ahead and add this 04:23.130 --> 04:24.720 keyword descend. 04:24.750 --> 04:29.880 And if I run this it's going to start from the last zero. 04:29.970 --> 04:32.910 And that is applicable to countries as well. 04:33.090 --> 04:36.870 You can also do that for dates if you go ahead and check dates. 04:37.050 --> 04:41.560 So we want to see dates underscore all that is in rule. 04:41.590 --> 04:43.420 Deeds in rule. 04:43.450 --> 04:44.980 Underscore dates. 04:45.850 --> 04:48.670 And then I have to change this to in rule. 04:49.930 --> 04:51.700 Underscore dates. 04:51.730 --> 04:53.650 And let's go ahead and execute the query. 04:53.650 --> 05:04.600 And uh we have 2050 1010 2050 uh 1007 both are different. 05:05.050 --> 05:09.970 And we have a total rule of guitar and 64 of 864. 05:10.450 --> 05:20.530 So the distinct value helps you to distinguish between repeated numbers of our data in a row and in 05:20.530 --> 05:21.100 a table. 05:21.130 --> 05:26.230 You actually get only one out of repeated values. 05:26.800 --> 05:27.580 How that is cool. 05:27.580 --> 05:33.190 So go ahead and apply this check it out program with it, and if you have any question, go ahead and 05:33.190 --> 05:34.690 use the question and answer section. 05:34.690 --> 05:37.180 And I'm going to get back to you as soon as possible. 05:37.210 --> 05:38.230 Thank you so much. 05:38.230 --> 05:41.110 And I'm going to see you in the next video lecture.