Let's take a look at how to work with dates and times in PHP.

Time inUnix-computers

For Unix computers, the time starts at midnight on January 1, 1970. Any date is calculated as the number of seconds (denoted by timestamp –– timestamp) that have passed since 01.01.1970. These conventions are also used in PHP. For example, we want to go one day ahead. Then you just need to add 60 × 60 × 24 seconds to the current timestamp value.

This time tracking scheme greatly facilitates the operations with dates. For example, if one timestamp value is greater than another, the first value is later than the second.

Time units per second

Getting the current time

In PHP, to get the current timestamp value, call the time () function without parameters, for example:

Many PHP functions for working with date and time take a timestamp value as an argument. For example, the date () function returns a formatted date string, for example:

Creaturetimestamp by date

Functionmktime() will create a timestamp if you specify hour, minute, second, day of month, month and year:

Functionstrtotime()

The function generates a timestamp for a date specified as a phrase in English, for example, April 1 or Friday.

The date value must be specified in the YYYY-MM-DD format. If the strtotime function cannot convert the date, it returns false.

Examples of using the functiondate ()

The built-in function floor () is used to discard the fractional part of the result.

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Date formats in databasesMySQL

The PHP timestamp format is incompatible with the MySQL timestamp format.

MySQL has three types of date and time fields: DATA (date), TIME (time), DATETIME (date and time). There is also a special data type TIMESTAMP, which works like DATETIME, but is automatically updated to reflect the current time each time a table record is inserted or updated.

To convert a timestamp in PHP format to MySQL format, you can use the following code:

Date ("Y-m-d H: i: s", $ timestamp)

For example, we can use “2008-10-01 13:23:40” as the date and time.

To get the PHP timestamp from a SELECT query, use the UNIX_TIMESTAMP () SQL function:

SELECT UNIX_TIMESTAMP (date) FROM table

MySQL has many other useful functions for working with date and time.

string date(string format[, int timestamp])

Returns the time formatted according to the argument format using the timestamp given by the argument timestamp or the current system time if timestamp not set. In other words, timestamp is optional and defaults to the value returned by the function time () .

Comment: For most systems, valid dates are December 13, 1901, 20:45:54 GMT through January 19, 2038, 03:14:07 GMT. (These dates correspond to the minimum and maximum value of a 32-bit signed integer.) For Windows, the valid dates are 01-01-1970 through 01.19-2038.

Comment: To get a timestamp from a string representation of a date, you can use the function strtotime ()... In addition, some databases have their own functions for converting the internal date representation to a timestamp (for example, the MySQL UNIX_TIMESTAMP function).

The following characters are recognized in the format parameter

Any other characters encountered in the string format, will be displayed in the resulting line without changes. Z always returns 0 when used gmdate () .

Examples of using the date () function

You can avoid recognizing a character as a formatting character by escaping the character with \. If a special character (for example, \ t) is combined with \, add another \.

Escaping characters in the date () function

The date function exists to display the time or date in a custom format.

This example displays the current date in day / month / year format as numbers. After reading this article to the end, you can display the current date and time in any format.
This function allows you to display not only the current date and time, but also convert the time stamp to a specified format. The timestamp is the number of seconds since linux was founded. This number can be obtained using the time () function. The timestamp in the date function is an optional parameter.To get the format you want, you can use special modifiers in the first parameter. There are a lot of them.

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Date and time representation

In distributed systems such as the Internet, time plays a special role. Due to a slight discrepancy in the system clock, a player in the Forex market can lose tens of thousands of dollars in a few minutes; the business intelligence system will make a mistake in forecasting; NNTP servers in the process of synchronization will lose important information needed by the user, etc.

PHP contains many functions for working with date and time. The most commonly used are:

• time ()- returns the current absolute time. This number is equal to the number of seconds that have passed since midnight January 1, 1970 (since the beginning of the UNIX era).
• getdate ()- reads information about date and time. Returns an associative array containing information for the specified time or for the current (by default) time. The array contains the following elements:

  Example 1

  $ val) echo "$ key = $ val
  "; echo"

  ---

  Today: $ d. $ D. $ D ";?>

  RESULT OF EXAMPLE 1:

  Seconds = 21 minutes = 4 hours = 12 mday = 10 wday = 4 mon = 11 year = 2005 yday = 313 weekday = Thursday month = November 0 = 1131613461 Today: 11/10/2005

• date ()- date and time formatting. Arguments: format string and absolute time. The second argument is optional. Returns a string with the specified or current date in the specified format. The format string can contain the following codes:

  a
  A	Included designation "AM" or "PM"
  d	Day of the month (01-31)
  D	Abbreviated name of the day of the week (three letters)
  F	Full month name
  g	Hours (12-hour format without leading zeros)
  G	Hours (24-hour format without leading zeros)
  h	Clock (12 hour format)
  H	Clock (24-hour format)
  i	Minutes (00-59)
  j	Day of the month without leading zeros (1-31)
  l	Full name of the day of the week
  L	Leap year (0 or 1)
  m	Month (01-12)
  M	Abbreviated month name (three letters)
  n	Month (1-12)
  s	Seconds (00-59)
  t	Number of days in a given month (28 to 31)
  U	Absolute time
  w
  y	Year (two digits)
  Y	Year (four digits)
  z	Day of the year (0-365)
  Z	Time zone offset in seconds (-43200 to 43200)

  Any other information included in the format string will be inserted into the returned string. If you want to add characters to the format string that are format codes themselves, you must precede them with a backslash "\". Characters that become format codes when added with a backslash must be preceded by two forward slashes. For example, if you want to add "n" to a string, you would enter "\\ n" because "\ n" is a newline character.

  Example 2

  RESULT OF EXAMPLE 2:

  Today: 10.11.05 13:03

• mktime ()- returns the absolute time, which can then be used with the date () or getdate () functions. Accepts up to six integer arguments in the following order:

  Clock
  minutes
  seconds
  month
  day of month
  year

  Example 3

  RESULT OF EXAMPLE 3:

• checkdate ()- checking the correctness of the date. Arguments: month, day, year. Returns true if the date is correct, i.e.
  month - an integer from 1 to 12;
  day is an integer not exceeding the total number of days in a given month. In this case, leap years are handled correctly;
  year is an integer from 1 to 32767.

  For example:

  If (! Checkdate ($ month, 1, $ year)) ($ d = getdate (); $ month = $ d; $ year = $ d;)

  Attention! The date can be in a valid range, but other date functions will not accept this value. So, you cannot use mktime () for years before 1902, and you should also use it carefully for years before 1970.

• strftime ()- formation of local date and time. Arguments: format string and absolute time. The second argument is optional. Returns a string with the specified or current date in the specified format. In this case, the names of months and days of the week are extracted from the locale selected using the Format string function can contain the following codes:

  % a	Abbreviated name of the day of the week
  % A	Full name of the day of the week
  % b	Abbreviated month name
  % B	Full month name
  % c	Preferred Date and Time Format
  % C	Century number
  % d	Day of the month (1-31)
  % D	Same as % m /% d /% y
  % e	Month (1-12)
  % h	Same as % b
  % H	Clock (24-hour format)
  % I	Clock (12 hour format)
  % j	Day of the year (0-365)
  % m	Month (1-12)
  % M	Minutes
  % n	Newline character
  % p	The designation "am" or "pm" is included
  % r	Time using a.m./p.m.-notation
  % R	Time in 24-hour format
  % S	Seconds (00-59)
  % t	Tab character
  % T	Same as % H:% M:% S
  % u	Day of the week number (1 - Monday, 7 - Sunday)
  % U	Week number. Countdown starts from the first Sunday of the year
  % V	ISO 8601: 1988 week number. The first week must have at least four days, and Monday is considered the first day
  % W	Week number. Countdown starts from the first Monday of the year
  % w	Day of the week number (0 - Sunday, 6 - Saturday)
  % x	Preferred date format without time
  % X	Preferred time format without date
  % y	Year (two digits)
  % Y	Year (four digits)
  % Z	Time zone (name or abbreviation)
  %%	The "%" character

  Any other information included in the format string will be inserted into the returned string.

(PHP 4, PHP 5, PHP 7)

date - Formats the output of the system date / time

Description

String date (string $ format [, int $ timestamp = time () ])

Returns a string formatted according to the specified format template. The timestamp specified by the timestamp argument is used, or the current system time if no timestamp is specified. So timestamp is optional and defaults to the value returned by the function time ().

Parameter List

The resulting string template ( string) with a date. See formatting options below. There are also several predefined date / time constants that can be used in place of these parameters. For example: DATE_RSS replaces template "D, d M Y H: i: s".

Any other characters encountered in the wildcard string will be printed to the resulting string unchanged. Z always returns 0 using gmdate ().

Comment:

Since the function in question takes as a parameter timestamps of the type integer formatting character u will only be useful when using the function date_format () and custom timestamps created with the function date_create ().

The optional timestamp parameter is integer a timestamp that defaults to the current local time if no timestamp is specified. In other words, the default is the result of the function time ().

Return Values

Returns a formatted date string. If you pass a non-numeric value as a parameter, timestamp will be returned FALSE and a level error is caused E_WARNING.

List of changes

Examples of

Example # 1 Examples of using a function date ()

// set the default timezone. Available since PHP 5.1
date_default_timezone_set ("UTC");

// will print something like this: Monday
echo date ("l");

// will output something like this: Monday 8th of August 2005 03:12:46 PM
echo date ("l jS \ of F Y h: i: s A");

// prints: July 1, 2000 is on a Saturday
echo "July 1, 2000 is on a". date ("l", mktime (0, 0, 0, 7, 1, 2000));

/ * an example of using a constant as a formatting parameter * /
// will output something like this: Wed, 25 Sep 2013 15:28:57 -0700
echo date (DATE_RFC2822);

// will output something like this: 2000-07-01T00: 00: 00 + 00: 00
echo date (DATE_ATOM, mktime (0, 0, 0, 7, 1, 2000));
?>

To prevent a character from being recognized as a formatting character, escape it with a backslash. If the escaped character is also a formatting sequence, then it SHOULD be re-escaped.

Example # 2 Escaping characters in a function date ()

// will print something like this: Wednesday the 15th
echo date ("l \ t \ h \ e jS");
?>

To display past and future dates, it is convenient to use the functions date () and mktime ().

Example # 3 Function sharing example date () and mktime ()

$ tomorrow = mktime (0, 0, 0, date ("m"), date ("d") + 1, date ("Y"));
$ lastmonth = mktime (0, 0, 0, date ("m") - 1, date ("d"), date ("Y"));
$ nextyear = mktime (0, 0, 0, date ("m"), date ("d"), date ("Y") + 1);
?>

Comment:

This method is more reliable than simple subtraction and addition of seconds to the timestamp, since it allows you to flexibly switch to summer / winter time if necessary.

A few more examples of using the function date ()... It is important to note that you should escape any characters that need to be left unchanged. This is also true for those characters that are not recognized as formatting characters in the current version of PHP, as this may be introduced in future versions. Single quotes should be used to escape escape sequences (for example, \ n).

Example # 4 Formatting using date ()

// Suppose the current date is March 10, 2001, 5:16:18 PM,
// and we are in the Mountain Standard Time (MST)

$ today = date ("F j, Y, g: i a"); // March 10, 2001, 5:16 pm
$ today = date ("m.d.y"); // 03.10.01
$ today = date ("j, n, Y"); // 10, 3, 2001
$ today = date ("Ymd"); // 20010310
$ today = date ("h-i-s, j-m-y, it is w Day"); // 05-16-18, 10-03-01, 1631 1618 6 Satpm01
$ today = date ("\ i \ t \ i \ s \ t \ h \ e jS \ d \ a \ y."); // it is the 10th day.
$ today = date ("D M j G: i: s T Y"); // Sat Mar 10 17:16:18 MST 2001
$ today = date ("H: m: s \ m \ i \ s \ \ m \ o \ n \ t \ h"); // 17:03:18 m is month
$ today = date ("H: i: s"); // 17:16:18
$ today = date ("Y-m-d H: i: s"); // 2001-03-10 17:16:18 (MySQL DATETIME format)
?>

To format dates in other languages, use instead date () functions setlocale () and strftime ().

Notes (edit)

Comment:

To get the timestamp from the string representation of the date, you can use the function strtotime ()... In addition, some databases have their own functions for converting the internal date representation to a timestamp (for example, the MySQL »UNIX_TIMESTAMP function).