Learn more about PHP date-time functions date ()

1, year-month-day
echo Date (' y-m-j ');
2007-02-6

echo Date (' y-n-j ');
07-2-6

Capital Y represents a four-digit year, while lowercase y represents a two-digit number for the year;
Lowercase m represents the number of months (with leading), while lowercase n indicates the number of months without leading.

echo Date (' y-m-j ');
2007-feb-6

echo Date (' y-m-d ');
2007-02-06

Uppercase M represents the 3 abbreviations for the month, while lowercase m represents the number of months (with a leading 0);
There is no uppercase J, only lowercase J indicates the date of the month, no leading o, and lowercase D if you want the month band leading.

echo Date (' y-m-j ');
2007-feb-6

echo Date (' Y-f-js ');
2007-february-6th

Capital M represents the 3 abbreviations of the month, while capital F indicates the full English of the month. (No lowercase f)
Uppercase S represents the suffix of a date, such as "St", "nd", "rd", and "th", depending on the date number.

Summary:
Indicates that the year can be in uppercase Y and lowercase y;
Indicates that the month can be in uppercase F, uppercase M, lowercase m, and lowercase n (two ways of representing characters and numbers, respectively);
Indicates that the day can be a suffix of a date with lowercase d and lowercase j, uppercase S.


2, when: minutes: seconds

By default, PHP interprets the time as "Greenwich Mean Time", which is 8 hours away from our local time.

echo Date (' g:i:s a ');
5:56:57 am

echo Date (' H:i:s A ');
05:56:57 AM

Lowercase g represents a 12-hour system with no leading 0, while lowercase h indicates a 12-hour system with a leading 0.
When using a 12-hour system, you need to indicate that in the afternoon, lowercase a is the lowercase "am" and "PM", and capital a denotes "AM" and "PM" uppercase.

echo Date (' g:i:s ');
14:02:26

Capital G represents 24 hours of hours, but not leading; use uppercase H to indicate a 24 hour system with a leading number of hours

Summary:
The letter G indicates that the hour is not leading, and the letter H denotes the hour with leading;
Lowercase g, h means 12-hour system, capital G, H is 24-hour system.

3, Leap year, week, day

echo Date (' L ');
Whether this year leap years: 0

echo Date (' L ');
Today is: Tuesday

echo Date (' D ');
Today is: Tue

Capital L indicates whether a leap year is a Boolean value that returns 1 for true or 0;
Lowercase L means the day is the week of the English full write (Tuesday);
Instead, use uppercase D to denote the 3-character abbreviation for the Day of the Week (Tue).

echo Date (' W ');
Today's Week: 2

echo Date (' W ');
This week is the No. 06 week of the year.

The lowercase w represents the day of the week, the number form represents
Capital W indicates the number of weeks in a year

echo Date (' t ');
This month is 28 days

echo Date (' Z ');
Today is the 36th day of the year.

Lowercase T represents the current month and how many days
Lowercase Z means today is the first day of the year

4, other

echo Date (' T ');
Utc
Capital T indicates the time zone setting of the server

echo Date (' I ');
0
Capital I indicates whether the current is daylight saving time, returns 1 for true, or 0

echo Date (' U ');
1170769424
The capital U represents the total number of seconds from January 1, 1970 to the present, which is the Unix time stamp for the Unix time era.

echo Date (' C ');
2007-02-06t14:24:43+00:00
Lowercase C represents the ISO8601 date, the date format is YYYY-MM-DD, the date and time is separated by the letter T, the time format is HH:MM:SS, and the time zone uses the deviation of Greenwich Mean Time (GMT).

echo Date (' R ');
Tue, Feb 2007 14:25:52 +0000
Lowercase R represents the RFC822 date.

The small date () function shows the power and charm of PHP, hehe.