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Finding the Length of Text
2:50You can obtain lengths of pieces of text using the LENGTH() function.
Imagine we're still working
on an e-commerce site.
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And the designers come up
to us to ask a question.
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They're updating the design
on a customer profile page.
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They want to know the length of
the largest user name in the database
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to test out if their design works at
the extremes of what's in our database.
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We can use the SQL function called
length to help us answer this question.
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We have a select statement that
only brings back the username
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from our customers table.
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Let's show the username and their
length of the username in the report so
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we can verify that it's actually working.
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Remember, a function starts with
the name of the function, length,
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a pair of parenthesis and
then the value or
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the column name that you
want to be transformed.
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Watch, when we run this,
we get the username with their lengths.
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Notice here, in the column names
that length username is shown.
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That's what happens when you don't
alias a result of a function.
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Let's alias this to something
that's easier to understand.
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That's better, but
what about the longest username?
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What is it?
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What new keywords have we learned
that we could use to figure this out?
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We can order by their
length in descending order.
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And then limit it to just the longest one.
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When we run it only the record with
the longest username is returned.
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There may be more with the same length,
but those results are irrelevant.
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All we want to know is the length.
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You're also not limited to using
the results of the function
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in the order by criteria.
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Let's say we wanted to find all usernames
under the length of seven characters.
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We could modify our
query to look like this.
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Where length is less than seven.
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In fact, you don't even need to select it.
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You can simply move it over
to the condition like this.
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You may want to do this, because
seeing the length doesn't matter, but
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the actual username is what's important.
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You've seen the length function
used in several different ways.
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You've seen it used in this
select portion of a query.
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We even saw it being used as
part of a where condition.
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You can include it anywhere you'd
put a value or column name.
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You should start to see how using
functions can help answer more questions
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or form an output.
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We're going to explore many more
functions throughout this course.
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