1
00:00:00,240 --> 00:00:00,780
Okay.

2
00:00:00,780 --> 00:00:02,070
So let's go over.

3
00:00:02,070 --> 00:00:03,270
Hopefully you're still alive.

4
00:00:03,600 --> 00:00:05,910
It was maybe a bit of a challenging problem set.

5
00:00:06,390 --> 00:00:10,080
But if you're still here, let's go with these first three.

6
00:00:10,380 --> 00:00:11,930
So evaluate the following.

7
00:00:11,940 --> 00:00:14,340
Select ten not equal to ten.

8
00:00:14,610 --> 00:00:16,950
Well, ten is equal to ten.

9
00:00:16,950 --> 00:00:19,320
So this should return false.

10
00:00:20,170 --> 00:00:23,940
We get zero next one, a little more complex.

11
00:00:24,360 --> 00:00:25,260
We've got an end.

12
00:00:25,260 --> 00:00:27,630
So remember, that means both sides have to be true.

13
00:00:28,040 --> 00:00:29,040
Start with the left.

14
00:00:29,040 --> 00:00:30,870
Is 15 greater than 14?

15
00:00:30,870 --> 00:00:32,159
Yes, that's true.

16
00:00:32,549 --> 00:00:33,870
But how about this side?

17
00:00:34,800 --> 00:00:36,480
99 minus five.

18
00:00:36,720 --> 00:00:38,280
It gives us 94.

19
00:00:38,310 --> 00:00:40,590
Is 94 less than or equal to 94?

20
00:00:40,740 --> 00:00:42,050
Yes, it's equal to.

21
00:00:42,330 --> 00:00:49,800
So that means both sides are true, meaning the whole thing is true, which we get one finally select

22
00:00:49,800 --> 00:00:54,090
one in five, comma three or nine between eight and ten.

23
00:00:54,420 --> 00:00:57,660
So we've got four means either side can be true.

24
00:00:57,660 --> 00:00:59,280
Four to make the whole thing true.

25
00:00:59,280 --> 00:01:03,750
So let's start with this select one in five comma three.

26
00:01:03,750 --> 00:01:10,140
Remember, this is I didn't show you this explicitly, but we saw how to use n, so you should know

27
00:01:10,140 --> 00:01:10,920
how it works.

28
00:01:10,920 --> 00:01:13,830
Is one in that set of five comma three?

29
00:01:14,490 --> 00:01:15,120
No.

30
00:01:15,120 --> 00:01:16,410
So this side is false.

31
00:01:16,650 --> 00:01:18,330
But that doesn't nullify the whole thing.

32
00:01:18,330 --> 00:01:24,300
That doesn't falsify it because what's on the right side is nine between eight and ten.

33
00:01:24,300 --> 00:01:25,170
Yes, it is.

34
00:01:25,170 --> 00:01:26,190
So this is true.

35
00:01:26,220 --> 00:01:27,840
Making the whole thing true.

36
00:01:28,800 --> 00:01:29,730
Let's try it.

37
00:01:31,740 --> 00:01:32,220
There we go.

38
00:01:32,220 --> 00:01:33,120
We get one.

39
00:01:33,300 --> 00:01:35,400
So false, true, true.

40
00:01:36,240 --> 00:01:40,440
Next, select all the books written before 1980.

41
00:01:40,530 --> 00:01:44,070
So I didn't specify what part of the book that's totally up to you.

42
00:01:45,030 --> 00:01:51,480
Let's just do title and release here so we can see that released here from books.

43
00:01:51,900 --> 00:01:58,890
And then the key thing is we want to do where release here is less than 1980 and not less than or equal

44
00:01:58,890 --> 00:02:04,860
to because it says non inclusive so less then where released here is less than 1980.

45
00:02:06,300 --> 00:02:07,470
Let's make sure it works.

46
00:02:08,910 --> 00:02:09,870
And there we go.

47
00:02:10,199 --> 00:02:11,880
All books are written before 1980.

48
00:02:11,910 --> 00:02:13,320
Apparently, we only have one.

49
00:02:13,320 --> 00:02:15,420
Let's just actually verify that.

50
00:02:15,750 --> 00:02:17,760
It's kind of catching me off guard there.

51
00:02:20,970 --> 00:02:23,280
And it looks like that's the case.

52
00:02:23,340 --> 00:02:24,930
All we have is Cannery Row.

53
00:02:26,350 --> 00:02:29,290
Well, I apologize that we don't have more exciting data.

54
00:02:30,100 --> 00:02:37,840
Next up, select all books written by Eggers or Shavon, which I know now know how to pronounce.

55
00:02:38,020 --> 00:02:39,790
So there's a couple of ways of doing this.

56
00:02:40,300 --> 00:02:46,780
Let's start with the most straightforward maybe, which would be, and also let's do title and author

57
00:02:46,810 --> 00:02:47,740
last name.

58
00:02:50,530 --> 00:02:53,700
So again, I didn't specify what parts he had to select.

59
00:02:53,950 --> 00:02:56,320
It's up to you, but this makes the most sense.

60
00:02:56,320 --> 00:02:58,000
So we can see the author last names.

61
00:02:58,780 --> 00:03:06,370
So what we can do is select them where and we can use an or so we can do a double equality where author

62
00:03:06,370 --> 00:03:14,650
last name is equal to Eggers or author last name is equal to Chabon, where author L name is equal to

63
00:03:14,680 --> 00:03:22,210
Eggers or author LL name is equal to Chabon just like that.

64
00:03:23,410 --> 00:03:25,060
That's one way of doing it.

65
00:03:25,450 --> 00:03:28,000
And you can see we get those for books.

66
00:03:29,110 --> 00:03:36,610
However, we can also use in because all that we're doing is trying to see if author ll name is in the

67
00:03:36,610 --> 00:03:43,720
set of Eggers and Chabon so we can combine them basically say where author l name in.

68
00:03:45,680 --> 00:03:46,640
That set.

69
00:03:48,450 --> 00:03:49,260
Copy that.

70
00:03:50,010 --> 00:03:50,640
And there we go.

71
00:03:50,640 --> 00:03:51,600
Same results.

72
00:03:51,600 --> 00:03:55,770
So whichever you prefer, this one is a little bit easier to see.

73
00:03:55,770 --> 00:03:56,700
I guess it's shorter.

74
00:03:56,700 --> 00:03:57,630
Easier to edit.

75
00:03:58,140 --> 00:04:03,150
And if we wanted to add another author in, it's pretty simple, but this is also perfectly valid.

76
00:04:04,740 --> 00:04:10,110
Next, select all the books written by Lahiri published after 2000.

77
00:04:12,030 --> 00:04:17,640
So the first thing we'll do title and this time we'll do author l name.

78
00:04:17,670 --> 00:04:18,149
Oops.

79
00:04:20,870 --> 00:04:24,050
And released here from books.

80
00:04:24,500 --> 00:04:27,080
And they'll start by all books written by Lahiri.

81
00:04:27,080 --> 00:04:33,050
So where author ll name equals Lahiri.

82
00:04:33,680 --> 00:04:34,910
So we can start there.

83
00:04:36,140 --> 00:04:42,350
We know that this should work, but we get two books, and now we want only the ones published after

84
00:04:42,350 --> 00:04:43,250
2000.

85
00:04:43,820 --> 00:04:53,510
So what we need is a logical and so where author l name is equal to Lahiri and released here is greater

86
00:04:53,510 --> 00:04:54,710
than 2000.

87
00:04:54,710 --> 00:04:57,860
And I didn't specify if it was inclusive or not.

88
00:04:57,860 --> 00:05:03,830
So based off of the language published after 2000 will keep it as a greater than if you put an equal

89
00:05:03,830 --> 00:05:04,280
sign there.

90
00:05:04,280 --> 00:05:04,940
It's not.

91
00:05:05,210 --> 00:05:06,950
I mean, you got it right, essentially.

92
00:05:07,610 --> 00:05:10,040
I didn't do a great job of clarifying that before.

93
00:05:10,040 --> 00:05:11,270
So either one works.

94
00:05:12,620 --> 00:05:14,330
Now we only get the namesake.

95
00:05:14,540 --> 00:05:16,430
Also really great read.

96
00:05:17,450 --> 00:05:22,840
Next up, select all books with page count between 102 hundred.

97
00:05:22,850 --> 00:05:27,540
So just like the problem we did back here, there is a couple of solutions.

98
00:05:27,560 --> 00:05:28,940
The first one is to use logical.

99
00:05:28,940 --> 00:05:40,160
And so we could do select title and page count or what is it just pages from books where pages is greater

100
00:05:40,160 --> 00:05:43,850
than 100 and less than 200.

101
00:05:44,510 --> 00:05:51,950
So where pages and we'll do greater than or equal to pages is greater than or equal to 100 and pages

102
00:05:51,950 --> 00:05:53,990
is less than or equal to 200.

103
00:05:55,280 --> 00:05:58,520
That's one way of selecting based off of a range there.

104
00:05:58,520 --> 00:06:06,020
We get these shorter books but we could also use between which maybe you gathered because of the language

105
00:06:06,020 --> 00:06:10,700
here it screams out between and that might simplify it a bit.

106
00:06:10,700 --> 00:06:16,820
So all we have to do is change it to where pages between 102 hundred.

107
00:06:18,740 --> 00:06:21,680
Nice easy to read version we get the same results.

108
00:06:22,980 --> 00:06:23,500
Okay.

109
00:06:23,610 --> 00:06:24,240
One thing.

110
00:06:24,270 --> 00:06:26,170
Remember that this is inclusive.

111
00:06:26,190 --> 00:06:34,230
So if we didn't want to include 102 hundred, we could either do this or we would have to change this

112
00:06:34,230 --> 00:06:38,040
to be 101 and 199 or something.

113
00:06:39,360 --> 00:06:40,980
So I'll leave it as 200.

114
00:06:42,360 --> 00:06:43,080
Moving on.

115
00:06:44,550 --> 00:06:48,780
Select all books where the author last name starts with a C or an SE.

116
00:06:49,050 --> 00:06:50,940
So there's also a couple of ways of doing this.

117
00:06:50,940 --> 00:06:51,360
One.

118
00:06:51,690 --> 00:06:54,600
We'll start with the simplest one.

119
00:06:55,320 --> 00:07:03,300
So we want to select and this time we'll do title and author L name from books.

120
00:07:03,570 --> 00:07:08,190
And basically we want to let's just type it out with pseudocode or English code.

121
00:07:08,190 --> 00:07:17,970
So where author l name starts with C or author.

122
00:07:21,970 --> 00:07:24,520
Our name starts with S.

123
00:07:24,970 --> 00:07:27,340
So those are not you know, that's not valid code.

124
00:07:27,520 --> 00:07:28,750
So how do we do this?

125
00:07:29,230 --> 00:07:30,470
There's a couple of options.

126
00:07:30,490 --> 00:07:36,820
The first one is to just use like if you're if you're comfortable with that instead of starts with C,

127
00:07:36,820 --> 00:07:45,910
we can just say wear author L name like and then we use the percent sign to force the C to be at the

128
00:07:45,910 --> 00:07:47,290
beginning of the string.

129
00:07:47,950 --> 00:07:51,940
So remember that this says string starts with C and then anything afterwards.

130
00:07:52,690 --> 00:07:59,980
So that's one way to say it starts with a C and then we just do the same thing down here, like S with

131
00:07:59,980 --> 00:08:01,780
the percent sign after that.

132
00:08:01,870 --> 00:08:03,550
And that should do it for us.

133
00:08:04,420 --> 00:08:09,970
So we get Chabon, Smith, Carver, Steinbeck, Saunders, good collection of authors.

134
00:08:10,690 --> 00:08:14,350
However, there's another way, which is to use substring.

135
00:08:14,890 --> 00:08:22,660
So if you remember substring, or maybe you remember me complaining about how there is also an abbreviated

136
00:08:22,660 --> 00:08:25,440
subset str version.

137
00:08:25,450 --> 00:08:26,380
So we could use that.

138
00:08:26,380 --> 00:08:36,280
So we could say we're author l name sub strip of author l name and we want one comma one which will

139
00:08:36,280 --> 00:08:41,950
give us the first character we want to check where that's equal to C or.

140
00:08:43,900 --> 00:08:48,580
And I'll just duplicate this whole thing where it's equal to sx.

141
00:08:49,660 --> 00:08:51,010
So we could do this.

142
00:08:53,370 --> 00:08:54,690
And we get the same thing.

143
00:08:55,350 --> 00:09:00,480
But there's yet another way to clean this up, which is to then I'll just keep them all here so that

144
00:09:00,480 --> 00:09:01,440
you can see them all.

145
00:09:02,250 --> 00:09:03,060
We could go.

146
00:09:03,060 --> 00:09:13,260
And because we're checking these two values, we could also use in C comma se just like that and get

147
00:09:13,260 --> 00:09:14,160
rid of the OR.

148
00:09:15,210 --> 00:09:19,980
So now we're saying select title and author l name from books where the first character of author l

149
00:09:19,980 --> 00:09:26,380
name is in the set of C or S and we get the same result.

150
00:09:26,400 --> 00:09:27,900
So three different ways.

151
00:09:28,800 --> 00:09:31,650
Next up, moving on to K statements.

152
00:09:31,890 --> 00:09:36,990
So in this one, I tried to throw you for a little bit of a curveball because unlike the other case

153
00:09:36,990 --> 00:09:39,880
statements we saw, we were just using greater than and less than.

154
00:09:39,900 --> 00:09:41,520
There's a couple of things you're doing here.

155
00:09:41,940 --> 00:09:47,760
So we're just working with Title, but you're seeing if title is like stories and then you're seeing

156
00:09:47,760 --> 00:09:51,840
if it exactly equals just kids or a heartbreaking work of staggering genius.

157
00:09:52,470 --> 00:10:00,150
So let's let's start off with the basics select title and author l name.

158
00:10:02,020 --> 00:10:05,410
And we'll just do from books just like that.

159
00:10:05,740 --> 00:10:08,470
And then we need our case statement syntax.

160
00:10:09,040 --> 00:10:15,820
So we're going to have case and I like to just put my end right in there as well as my as and I called

161
00:10:15,820 --> 00:10:21,760
it type, which I don't actually think is a great name genre would be better, but inside of here we're

162
00:10:21,760 --> 00:10:22,930
going to have our statements.

163
00:10:23,440 --> 00:10:30,040
So the first thing we're going to do is figure out, okay, if title contains the word stories anywhere,

164
00:10:30,370 --> 00:10:31,720
type is short stories.

165
00:10:33,280 --> 00:10:38,390
So when title like and how do we write it?

166
00:10:38,410 --> 00:10:43,480
Express the fact that it can contain stories anywhere, not just at the beginning, but anywhere in

167
00:10:43,480 --> 00:10:43,860
there.

168
00:10:43,870 --> 00:10:45,880
Well, we use parentheses.

169
00:10:45,880 --> 00:10:47,290
Excuse me, percent sign.

170
00:10:48,130 --> 00:10:54,340
So this means that it contains a string stories with anything afterwards, which technically we could

171
00:10:54,340 --> 00:10:56,530
have histories or something.

172
00:10:56,860 --> 00:10:57,450
Whoops.

173
00:10:57,670 --> 00:11:01,000
Which maybe is not what we want, but we can leave it at that.

174
00:11:01,000 --> 00:11:04,390
You could put a space here or something to make sure that it's just stories.

175
00:11:04,390 --> 00:11:14,710
But I'll keep it simple with stories like this, then that's going to be short stories as our type.

176
00:11:17,350 --> 00:11:25,270
Then we have another statement when title and when title is exactly just kids or a heartbreaking work

177
00:11:25,270 --> 00:11:26,530
of staggering genius.

178
00:11:27,040 --> 00:11:32,980
We should print out memoir, so let's leave that part blank and just add in then.

179
00:11:35,460 --> 00:11:36,210
Memoir.

180
00:11:37,860 --> 00:11:39,340
So then how do we fill this part in?

181
00:11:39,450 --> 00:11:41,070
There's it's pretty straightforward.

182
00:11:41,080 --> 00:11:42,510
It's going to be a bit annoying.

183
00:11:42,510 --> 00:11:52,140
So how do we check if it's equal to just kids when title equals just kids or when title equals?

184
00:11:52,140 --> 00:11:55,410
And this is going to be very long, so I'm going to copy it.

185
00:11:55,710 --> 00:11:56,520
Where are you?

186
00:11:59,570 --> 00:12:00,440
Just like that.

187
00:12:03,250 --> 00:12:05,110
And I might shorten that.

188
00:12:05,160 --> 00:12:06,280
I definitely would shorten it.

189
00:12:06,280 --> 00:12:11,620
So maybe it would be better to use like or something and search for a particular part rather than the

190
00:12:11,620 --> 00:12:12,540
entire name.

191
00:12:12,550 --> 00:12:20,500
But that was a problem here, followed by our else, which is otherwise everything is a novel.

192
00:12:21,940 --> 00:12:24,880
So that's where this comes in else.

193
00:12:26,170 --> 00:12:26,710
Novel.

194
00:12:26,890 --> 00:12:27,850
Just like that.

195
00:12:29,110 --> 00:12:30,090
Now let's double check.

196
00:12:30,100 --> 00:12:33,100
We don't have any extra commas, which I said I sometimes do.

197
00:12:33,670 --> 00:12:34,600
Looks good.

198
00:12:34,630 --> 00:12:35,680
Let's try it out.

199
00:12:37,630 --> 00:12:43,420
And we get all novels except for just kids.

200
00:12:43,420 --> 00:12:45,520
And a heartbreaking work is staggering genius.

201
00:12:46,060 --> 00:12:47,350
And then those are memoirs.

202
00:12:47,350 --> 00:12:52,060
And then we have two Raymond Carver collections of short stories and a David Foster Wallace collection.

203
00:12:53,510 --> 00:12:54,520
Okay, so that's it.

204
00:12:54,520 --> 00:13:00,040
And of course, you could clean this up so you could have used in here title equals.

205
00:13:00,040 --> 00:13:03,430
So you can say where title in Just Kids Comma a heartbreaking work.

206
00:13:03,430 --> 00:13:04,500
Staggering genius.

207
00:13:04,510 --> 00:13:10,960
You could use like something like this or a title like Heartbreaking.

208
00:13:11,110 --> 00:13:16,930
Although maybe we have multiple books with heartbreaking the title, so I'm going to leave that and

209
00:13:16,930 --> 00:13:18,460
move on to our final one.

210
00:13:19,240 --> 00:13:20,590
How do we make this happen?

211
00:13:20,620 --> 00:13:21,910
So again, what's happening?

212
00:13:21,910 --> 00:13:26,650
We're grouping things by author and we're counting how many books each author has written.

213
00:13:26,980 --> 00:13:29,070
But we're not just printing that out.

214
00:13:29,080 --> 00:13:34,960
We're printing it along with a space and then the correctly plural sized version of books.

215
00:13:35,620 --> 00:13:37,480
So we'll start by just printing out.

216
00:13:37,480 --> 00:13:42,460
We can ignore title, just do author last name and account without the books part.

217
00:13:43,680 --> 00:13:46,200
So that should be review of group by and count.

218
00:13:46,200 --> 00:13:48,690
So we'll select author.

219
00:13:51,360 --> 00:14:03,360
L name comma count star from books group by and we need to group by author.

220
00:14:04,740 --> 00:14:06,210
So if we do this.

221
00:14:07,260 --> 00:14:07,770
Oops.

222
00:14:11,430 --> 00:14:16,910
You'll see we end up with Carver has two books, Eggers has three books and so on.

223
00:14:16,920 --> 00:14:23,010
We do have that problem with Harris having two books, so we need to make this more specific where we

224
00:14:23,010 --> 00:14:25,320
also group by author first name.

225
00:14:26,010 --> 00:14:28,020
And now we have two different heresies.

226
00:14:28,020 --> 00:14:28,740
Perfect.

227
00:14:29,070 --> 00:14:36,510
So now how do we, instead of just printing count like this, how do we add in that variable the changeable

228
00:14:36,510 --> 00:14:39,980
suffix book or books that uses the case statement?

229
00:14:39,990 --> 00:14:41,610
So I'm going to make some space here.

230
00:14:41,910 --> 00:14:49,740
And rather than just printing the count, we're going to add in our case, case end.

231
00:14:50,010 --> 00:14:53,430
And if you look at how I printed it, I just called it count.

232
00:14:54,030 --> 00:14:55,590
So end as count.

233
00:14:56,010 --> 00:14:57,570
Then what is the logic?

234
00:14:57,570 --> 00:14:59,190
We're actually trying to do what?

235
00:14:59,190 --> 00:15:02,970
We're trying to figure out when the number of books Count Star.

236
00:15:03,940 --> 00:15:05,860
Is equal to one, let's say.

237
00:15:06,250 --> 00:15:07,780
Then we want to do something.

238
00:15:08,020 --> 00:15:10,480
Let's just say singular book.

239
00:15:10,510 --> 00:15:11,770
This isn't the right answer.

240
00:15:12,820 --> 00:15:13,900
Otherwise.

241
00:15:15,590 --> 00:15:17,150
We'll do books.

242
00:15:18,950 --> 00:15:21,380
So the logic is going down the right page.

243
00:15:21,380 --> 00:15:23,150
Regrouping Things by author.

244
00:15:23,390 --> 00:15:28,370
Then we're having a case statement that says When the total count of the number of books that authors

245
00:15:28,370 --> 00:15:32,870
written is equal to one, then count is book.

246
00:15:33,170 --> 00:15:36,170
And before I forget, we are missing our thens.

247
00:15:36,920 --> 00:15:41,210
So when count equals one, then book, that's very important.

248
00:15:42,170 --> 00:15:45,050
Now if we paste it so we get.

249
00:15:45,050 --> 00:15:46,550
Carver has books.

250
00:15:47,270 --> 00:15:50,800
Eggers has books, but each Harris has book.

251
00:15:50,810 --> 00:15:51,650
So we're close.

252
00:15:51,650 --> 00:15:53,510
But how do we get the number in there?

253
00:15:54,260 --> 00:15:56,000
And we need to use Cat.

254
00:15:56,120 --> 00:15:57,440
Hopefully you guessed that.

255
00:15:57,650 --> 00:15:59,540
So we're going to King Cat.

256
00:15:59,540 --> 00:16:03,500
Basically, we want to take the number which is going to be count.

257
00:16:05,350 --> 00:16:08,740
And we want to concatenate it with space book.

258
00:16:09,840 --> 00:16:14,610
Now if we want to shorten this, we could just hard code this as one book, right.

259
00:16:14,610 --> 00:16:19,230
Because when count is equal to one, then it's always going to be one book.

260
00:16:19,350 --> 00:16:21,840
This is the one where we have multiple books.

261
00:16:21,840 --> 00:16:27,210
We need to add in the number because it could be two books, it could be ten books.

262
00:16:27,510 --> 00:16:35,160
So we'll can cat the two pieces, which are going to be count star comma.

263
00:16:36,540 --> 00:16:39,420
And I know this looks like a lot here, so let's step through it.

264
00:16:40,080 --> 00:16:43,770
Concatenate the count with space books.

265
00:16:43,770 --> 00:16:45,270
So two books.

266
00:16:45,270 --> 00:16:46,320
Three books.

267
00:16:47,520 --> 00:16:48,840
And that should do it.

268
00:16:51,800 --> 00:16:52,850
Let's double check.

269
00:16:54,050 --> 00:16:54,770
Here we go.

270
00:16:54,800 --> 00:16:56,030
Carver has two books.

271
00:16:56,030 --> 00:16:57,260
Chabon has one book.

272
00:16:57,290 --> 00:16:58,510
Harris has one book.

273
00:16:58,520 --> 00:16:59,870
Lahiri has two books.

274
00:16:59,900 --> 00:17:05,720
The only other improvement, I guess, to suggest would be to also put author first name, just to make

275
00:17:05,720 --> 00:17:06,710
it a little clearer.

276
00:17:07,250 --> 00:17:12,660
In the case of Harris, we now can see Dan Harris has one book in free to.

277
00:17:12,680 --> 00:17:13,700
Harris has one book.

278
00:17:13,940 --> 00:17:15,500
Jhumpa Lahiri has two books.

279
00:17:16,400 --> 00:17:17,420
Oh, right.

280
00:17:17,690 --> 00:17:18,740
Quite a bit there.

281
00:17:18,890 --> 00:17:20,060
Hopefully you made it through.

282
00:17:20,150 --> 00:17:21,579
Time to move on.

283
00:17:21,589 --> 00:17:24,810
We can burn that part of us that's attached to the books.

284
00:17:24,829 --> 00:17:25,790
We are done.

285
00:17:25,819 --> 00:17:28,160
We're moving on to bigger, more exciting things.

286
00:17:28,190 --> 00:17:34,610
I highly recommend that you, if you're at your computer, get up and take a break because joins are

287
00:17:34,610 --> 00:17:35,240
a big section.

288
00:17:35,240 --> 00:17:37,100
Very important stuff coming up next.

289
00:17:37,280 --> 00:17:38,300
But a bit dense.

290
00:17:38,300 --> 00:17:46,670
So go for a walk if you'd like or do whatever you need to do to get prepared to focus on joins.