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Now we know how to make a date time
object,

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we should learn how to do things with
them.

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One of the first things we might like to
do is compare dates.

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Date comparisons are made very easy in
PHP.

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Many older tutorials will suggest you have
to turn all dates into Unix time

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stamps before you can compare the number
of seconds, but

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date time objects can be compared
directly.

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Try and steer clear of the old date, and
STR time functions.

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And definitely avoid adding and
subtracting specific numbers of

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seconds to change dates due to time zone
complications.

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Let's take a look at time zones in the
next video.

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Let's open the index.php file in our work
space now.

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And have a look at another handy feature
of date time that is often under utilized.

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On lines three and four, we are creating
two new date time objects,

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both of which contain dates in their
supported format.

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On line three, there is an object named
dvone.

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And on line four contains an object named
spike.

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These daytime objects represent the
birthdays of famous

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WWE wrestlers D-Von Dudley and Spike
Dudley.

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Below that on line eight is an if
statement.

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This if statement is comparing which is
lesser out of the two objects.

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At first it might seem odd to compare two
objects directly, but when this is used,

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the internal values of the date,
regardless of the format they were

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created with will be compared to see which
is the lesser of the two.

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Think about it.

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If somebody is born in 1900, then that is
a small number than 2000.

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00:01:19,700 --> 00:01:23,650
And somebody born in 1900 is certainly
older than someone born in 2000.

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When we run this we should expect to see
the paragraph Spike is

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older than D-Von output.

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As Spike was born in 1970, almost two
years before D-Von.

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Great our if statement worked, and we know
who is older.

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Comparisons are useful, but

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we can also look at the actual difference
between the two dates.

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This will let us see what the age gap
really is.

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So we go back to our workspace here.

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Uncomment these lines.

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Refresh that.

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There we have it.

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There is one year, 11 months, and 19 days
between Spike and D-Von.

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But how do we do that.

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On line 16, we are creating an object and
storing it in a variable called diff.

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This object is an instance of date time
interval.

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And that means we can call methods on it.

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One method we recall is the format method.

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This is a little different to the
DateTime Format method, but

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it works in much the same way.

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We can pass it as string and use certain
characters preceded by a percentage sign

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to denote actual values that represent a
portion of the difference.

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For example, we have a percent y, which
will show the number of years,

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a percent m, which shows the number of
months.

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And percent d, which you guessed it, shows
the number of days.

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That's a good introduction to DateTime and
comparisons.

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So, now we're gonna move on to time zones.