WEBVTT 00:00.090 --> 00:02.150 Okay I'm back with a very quick EDITION. 00:02.150 --> 00:07.560 This is a frequently asked question that I get pretty often which is is there really a big difference 00:07.560 --> 00:12.130 between right and left joins if we just change the order of what we're joining. 00:12.150 --> 00:14.650 And the answer is No they're actually the same. 00:14.790 --> 00:18.460 So if we do a left join where this is customers a. 00:18.930 --> 00:24.170 And then on the right we have orders that's identical to doing a RIGHT JOIN. 00:24.540 --> 00:29.950 If instead we put customers over here and we put orders under way. 00:30.180 --> 00:34.740 So think of it as just you know flipping this there's no difference. 00:34.740 --> 00:36.210 So let me show you an example. 00:36.360 --> 00:42.460 If we go and we go grab our simple left join from way back here. 00:42.800 --> 00:50.270 This one right here simpleness left join and I will paste it down here just you have it to see. 00:50.270 --> 00:51.610 And let's paste it in as well. 00:51.910 --> 00:52.180 OK. 00:52.200 --> 00:54.860 First of all there's a lot to look at right. 00:55.140 --> 01:02.190 But what's most important is that we have on the left customer's information first and then on the right 01:02.550 --> 01:05.110 we have our order information right. 01:05.370 --> 01:08.380 And then we have Knoll's where we don't have a matching order. 01:08.690 --> 01:09.300 OK. 01:09.720 --> 01:13.540 So what happens if we try and do the same thing. 01:13.800 --> 01:23.580 But instead of doing customers first we do orders and we do a right join customers on customers that 01:23.580 --> 01:26.920 ID equals orders customer ID. 01:27.510 --> 01:28.450 OK. 01:28.830 --> 01:33.870 So if we do this look at what we get here. 01:34.300 --> 01:36.860 So we have the exact same data. 01:36.930 --> 01:44.600 One two three four five rows one two three four five but the order that they're printed is different. 01:44.620 --> 01:45.540 Right. 01:45.580 --> 01:53.920 So we have on the left side now we have our orders information and then on the right we have our customers 01:53.920 --> 01:58.470 information but the actual data that's displayed is the same. 01:58.510 --> 02:02.620 Yes the order changes but that's know trivial. 02:02.620 --> 02:04.030 That doesn't matter. 02:04.030 --> 02:06.690 So in effect these are equivalent. 02:06.910 --> 02:13.390 And in fact some like some environments that I've come across some developing environments won't even 02:13.390 --> 02:19.290 support a right join and they just want to do a left join and switch the order. 02:20.080 --> 02:25.990 So to actually to sum up one more time let's say I did the same thing here with orders and customers 02:26.550 --> 02:28.870 but I did a left join. 02:28.870 --> 02:30.500 What would happen now. 02:30.640 --> 02:33.760 What's a left join with orders first and then customers. 02:34.390 --> 02:39.200 And the answer is it's the same as doing a right join. 02:39.520 --> 02:44.850 Except if we start with customers and then orders. 02:46.380 --> 02:52.720 And unfortunately we don't really have anything to see right because our data doesn't have any discrepancies 02:52.720 --> 02:53.650 on the order side. 02:53.650 --> 02:59.080 This was the entire last video was about which I will not retread here but my point is that they look 02:59.080 --> 03:04.060 the same and they look just like an inner join us well but when we have something different like with 03:04.210 --> 03:08.820 our left join for customers and orders you can see that the data is actually the same.