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Let me ask the audience, what style mistake did
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I just make when I typed in this query?
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So I'm seeing maybe I used double quotes when I should have used single quotes.
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So let me come back and fix that first.
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I'll come back over here.
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And, again, by convention, we tend to use single quotes for our strings.
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So let me fix that right here.
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And now let me run this query to see what we get back.
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I'll hit Enter.
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And I'll see only those books that begin with "The."
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Now, let me show this query again, though.
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This was our query here.
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Knowing what we know about the percent sign,
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what other titles might I accidentally get back by running this query?
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I have "The" percent.
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But what other words actually begin these book titles
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if I were to run this query here?
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We saw only those with "The," but if I had other book titles, what might
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I get back?
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1.52
So I might get back those book titles that
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have not just "The" the beginning but also, let's say,
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"There" or "They" or so on.
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There are many words beginning with T-H-E.
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And if I had the percent sign right after it,
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I might match one of those words like Y or R-E or so on.
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So I didn't have any of those titles in this database.
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But you can imagine a different database where I have that kind of data.
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Let's fix this then.
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I say, I want to match not just "The" but "The" and a space,
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and match any characters after that to make this
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query better designed in this instance.
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4.28
OK.
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0.83
So let me pause here then and ask what questions we
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have on using percent along with LIKE.
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5.24
SPEAKER: Can we use two percent signs between two words?
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CARTER ZENKE: Yeah, I think so.
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So let me go back to my terminal here and let me try to answer this question.
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So can we use two percent signs to say something's between two words?
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So let me say this.
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I'll go with SELECT, let's say, "title" from "longlist" WHERE maybe
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the "title" has something like--
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maybe it begins with "The."
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So I'll say WHERE "title" LIKE "The."
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And then I'll take any set of characters afterwards.
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3.57
But I want to have "love" also in here too.
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2.85
So I'll say "love."
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1.44
And then I'll take any other characters after it, percent again, single quote,
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6.43
Semicolon.
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1.38
Now, I don't know if I have any books that actually fit this search.
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But I could say the percent love percent to mean give me
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back any title that has "The" at the beginning
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then any words or characters then "love" then any words or characters
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after that.
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I'll hit Enter.
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And I see I don't have any books that fit that kind of description.
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But if I did, I would see them here with "The" at the beginning and "love"
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somewhere in the title.
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3.29
All right.
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0.5
So let's keep going.
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0.833
Let's focus not just on this percent sign, but also on this underscore.
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4.977
So if I want to find--
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let's say, I don't know what a particular character is in my title.
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I could use this underscore to match any particular character.
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Not any string of characters, but any single character too.
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3.24
So let's try this in our terminal.
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And there is a book, this one called a Pyre.
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3.18
And I actually keep forgetting how it's spelled.
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2.73
I don't know whether it's P-I-R-E or P-Y-R-E. It could be either one,
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but I want to find it in my database.
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2.07
So let me try this.
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I'll say SELECT, let's say, "title" FROM "longlist," WHERE, in this case,
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"title" is LIKE--
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well, I know that it starts with a P. And I
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don't know if this is an I or a Y. But I'll at least leave it as an underscore
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4.26
now to say it could be any character here.
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2.88
Then I'll say R-E single quote, Semicolon.
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5.92
And now I could try hitting Enter.
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2.06
And I'll see I get back this title called Pyre.
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3.96
So notice in this case that the underscore is matching
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literally any single character.
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2.25
This could be a Y. It could be an I. But in this case, I have this Y here.
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5.92
OK.
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0.605
Let me go back.
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0.625
And let's actually ask in this case what questions we
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have on using LIKE with these single underscores if any.
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SPEAKER: Yeah.
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So Carter, I wanted to ask you, that as you use the underscore sign here,
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so for multiple characters, can we use multiple underscores in order
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to find something in the database?
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CARTER ZENKE: A great question.
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Could we use more than one underscore to try to find
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some characters in our database?
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1.333
You absolutely could.
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0.875
So let me try that myself.
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1.525
I'll go back to my terminal.
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2.13
And let me try to find a book title this could work with.
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2.88
I'll say maybe SELECT "title" from "longlist"
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to get back all the books in this table.
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2.28
I'll hit Semicolon.
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1.32
And maybe I will go with--
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2.775