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So let's talk about solutions to these.

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The first one to delete all four year old cats.

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All we need to do is start off and you don't have to do this.

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But I like to start off by making sure we're selecting things correctly.

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So select start from cats where age equals four, we get Ringo.

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Then I just like to copy this.

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And do a delete from cats.

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And of course I forgot to add a space but delete from cats for ages four.

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Now if we do a let's do our first select, we should see nothing.

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And if we do a select star.

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We should see that we're now missing number one.

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Who was Ringo by Ringo.

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Next up, delete cats whose age is the same as their cat ID.

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So this one involved something slightly different, like I mentioned, where we're not just checking

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for a specific piece of data like breed equals Maine -- or age equals 12.

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But we're checking where cat ID equals age.

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So we'll do a select first select star from cats where cat ID equals H.

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Or you could do age equals cat ID and we get jack cat ID is seven age seven.

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Great.

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So then we'll just copy this.

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And do our delete from cats where cat id equals age.

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It says one row affected.

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If we try and select it again, it's gone.

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And if we do a select star now, we're also missing Jack.

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You can see we just have two, three, five and six, which leads us to our final example.

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Delete all cats.

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So this one is pretty straightforward.

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If we try to do the equivalent select, it would just be select star from cats with no ensuing where

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clause.

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Just like that.

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So to delete all of those, well, it's just delete from cats.

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All of our cats are being released at once into a land of rainbows and joy.

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We hit enter here.

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They're definitely 100% not dying.

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Nothing bad will ever happen to them.

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Here we go.

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Ford Rose affected select star from Cats The moment of truth.

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And they're all gone and not dead.

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Okay, so we've now covered the C and the R and the U and the D and crud that spells crud, which means

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that we're done with this.

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Next up, we'll get some practice putting it all together.