WEBVTT 00:00.060 --> 00:03.160 So let's talk about solutions to these. 00:03.180 --> 00:05.870 The first one to delete all four year old cats. 00:06.120 --> 00:11.040 All we need to do is start off and you don't have to do this but I like to start off by making sure 00:11.040 --> 00:17.620 we're selecting things correctly just like start from cats where age equals four. 00:17.790 --> 00:20.940 We get Ringo and I just like to copy this 00:23.760 --> 00:28.520 and do a delete from cats. 00:29.160 --> 00:36.720 And of course I forgot to add a space but the tweet from cats for ages for now if we do a let's do our 00:36.720 --> 00:39.680 first select We should see nothing. 00:39.680 --> 00:41.340 And if we do a select star 00:44.090 --> 00:49.560 we should see that we're now missing number one who was Ringo by Ringo. 00:49.940 --> 00:50.940 OK. 00:51.020 --> 00:52.840 Next up do eat cats. 00:52.840 --> 00:56.570 Whose age is the same as their cat ID. 00:56.870 --> 00:59.420 So this one involved something slightly different. 00:59.420 --> 01:05.240 Like I mentioned where we're not just checking for a specific piece of data like Breede equals Maine 01:05.240 --> 01:10.050 Coon or age equals 12 but we're checking we're cat ID equals age. 01:10.310 --> 01:20.800 So we'll do a select first Nexstar from cats where cat ID equals H. 01:20.930 --> 01:26.180 Or you could do Agios cat ID and we get Jack Kaede idea seven ages 7. 01:26.210 --> 01:27.010 Great. 01:27.350 --> 01:29.120 So then we'll just copy this 01:32.670 --> 01:39.530 and do our delete from cats where cat equals age says one row affected. 01:39.540 --> 01:41.580 If we try unselected again it's gone. 01:41.870 --> 01:46.160 If we do a select star now we're also missing Jack. 01:46.260 --> 01:52.480 You can see we just have two three five and six which leads us to our final example. 01:52.530 --> 01:54.390 Eat all cats. 01:54.390 --> 01:57.360 So this one is pretty straightforward. 01:57.930 --> 02:03.780 If we tried to do the equivalent select it would just be select star from cat with no ensuing where 02:03.780 --> 02:07.050 clause just like that. 02:07.080 --> 02:08.680 So to delete all of those. 02:08.880 --> 02:12.940 Well it's just the leads from cats. 02:13.050 --> 02:17.570 All of our cats are being released at once into a land of rainbows and joy. 02:17.730 --> 02:21.320 We hit enter here they're definitely 100 percent not dying. 02:21.630 --> 02:23.600 Nothing bad will ever happen to them. 02:23.790 --> 02:24.420 Here we go. 02:25.820 --> 02:32.130 For those affected selected star from cats the moment of truth. 02:32.690 --> 02:35.070 And they're all gone and not it. 02:35.450 --> 02:40.580 OK so we've now covered the C and R in the U and the D in crud that spells crud. 02:40.730 --> 02:41.960 Which means we're done with this. 02:41.960 --> 02:44.710 Next up we'll get some practice putting it all together.