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The powerful comparison
operators we've been using

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can also be used with date types.

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Let's look at a couple of
examples to see how they work.

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Let's take a look at our loans table and
ask some real life questions.

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Let's find out what are all the loans
that happened before December 13th, 2015?

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We can use a where clause.

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Remember, a where clause is
column, operator, and value.

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The column to answer this
question is loaned_on,

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And the value is 2015-12-13.

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Now, which operator do we use?

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Less than, or greater than?

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Since we're looking for dates before
the value on the right hand side,

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we want to use the less than operator.

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All dates before a given date value
are considered less than the value.

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All these results are the loans
before December 13th, 2015.

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Okay, let's take a look
at another question.

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Imagine today is December 18th, 2015.

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We want to send out a reminder to all
those who have books due back soon.

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So the question would be which
books are due back soon?

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Let's copy and paste this template
here and fill in the condition.

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For the condition this time we
want to use the return_by column.

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The value is 2015.

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-12-18.

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Since we wanted dates after a date value,

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we use the greater than
operator in this case.

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Awesome.

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This query has returned
all loans whether or

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not the books have already
been returned to the library.

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A little later on I'll show you how to
make this query return just the loans

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that haven't been returned to the library.

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Now we can find the patrons
with the IDs of 1 or 3,

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send them an email reminder
to return their books.

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We don't need to email patron 4 because
they returned their books on the 17th.