PHP MySQL date and time function collection _php tips

Collect the Compare full MySQL date and MySQL time function
Date_format (Date,format)
Formats the date value based on the format string. The following modifiers can be used in the format string:%m month name (January ...). December)
%w Week name (Sunday ...) Saturday)
%d The date of the month with English prefix (1st, 2nd, 3rd, and so on). ）
%Y years, numbers, 4-bit
%y years, numbers, 2-bit
%a name of the week (Sun ...) Sat)
Days in%d months, numbers (00 ...). 31)
%e the number of days in the month, numbers (0 ...). 31)
%m Month, number (01 ...) 12)
%c month, number (1 ...). 12)
%b abbreviated month name (...) DEC)
%j the number of days in a year (001 ...). 366)
%H hours (00 .....) 23)
%k hours (0 .....) 23)
%h hours (01 .....) 12)
%I Hours (01 .....) 12)
%l hours (1 .....) 12)
%i minutes, Number (00 .....) 59)
%r time, 12 hours (Hh:mm:ss [ap]m)
%T time, 24 hours (HH:MM:SS)
%s seconds (00 ...). 59)
%s seconds (00 ...). 59)
%p am or PM
%w the number of days in one weeks (0=sunday ...). 6=saturday)
%u weeks (0 .....) 52), here Sunday is the first day of the week
%u weeks (0 .....) 52), here Monday is the first day of the week
Percent% of a text "%".

All other characters do not interpret are copied into the result.

Mysql> Select Date_format (' 1997-10-04 22:23:00 ', '%w%m%Y ');
-> ' Saturday October 1997 '
Mysql> Select Date_format (' 1997-10-04 22:23:00 ', '%h:%i:%s ');
-> ' 22:23:00 '
Mysql> Select Date_format (' 1997-10-04 22:23:00 ',
'%d%y%a%d%m%b%j ');
-> ' 4th Sat Oct 277 '
Mysql> Select Date_format (' 1997-10-04 22:23:00 ',
'%H%k%I%r%T%s%w ');
-> ' 10:23:00 PM 22:23:00 00 6 '
In MySQL3.23,% is required before formatting modifiers. In the earlier version of MySQL,% is optional.

Time_format (Time,format)
This is used like the Date_format () function above, but the format string can contain only those formatting modifiers that handle hours, minutes, and seconds.

Other modifiers produce a null value or 0.
Curdate ()

Current_date
Returns the Today date value in ' Yyyy-mm-dd ' or YYYYMMDD format, depending on whether the function is used in a string or a numeric context.
Mysql> select Curdate ();
-> ' 1997-12-15 '
Mysql> Select curdate () + 0;
-> 19971215

Curtime ()

Current_time
Returns the current time value in ' HH:MM:SS ' or HHMMSS format, depending on whether the function is used in a string or in the context of a number.
Mysql> select Curtime ();
-> ' 23:50:26 '
Mysql> Select Curtime () + 0;
-> 235026

Now ()

Sysdate ()

Current_timestamp
Returns the current date and time in the ' Yyyy-mm-dd HH:MM:SS ' or YYYYMMDDHHMMSS format, depending on whether the function is in a string or a numeric
Context is used.
Mysql> Select Now ();
-> ' 1997-12-15 23:50:26 '
Mysql> Select now () + 0;
-> 19971215235026

Unix_timestamp ()

Unix_timestamp (date)
Returns a UNIX timestamp (the number of seconds since ' 1970-01-01 00:00:00 ' GMT) if no parameter calls are invoked. If Unix_timestamp () is invoked with a date parameter, it returns the number of seconds that start from ' 1970-01-01 00:00:00 ' GMT. Date can be a date string, a DateTime string, a timestamp, or a number of local time in YYMMDD or YYYYMMDD format.
Mysql> select Unix_timestamp ();
-> 882226357
Mysql> Select Unix_timestamp (' 1997-10-04 22:23:00 ');
-> 875996580

When Unix_timestamp is used in a timestamp column, the function will accept the value directly, without the implied "String-to-unix-timestamp" transformation http://www.knowsky.com/.

From_unixtime (Unix_timestamp)
Returns the value represented by the Unix_timestamp parameter in ' Yyyy-mm-dd HH:MM:SS ' or YYYYMMDDHHMMSS format, depending on whether the function is used in a string or a numeric context.
Mysql> Select From_unixtime (875996580);
-> ' 1997-10-04 22:23:00 '
Mysql> Select From_unixtime (875996580) + 0;
-> 19971004222300

From_unixtime (Unix_timestamp,format)
Returns a String representing the Unix time token, formatted according to the format string. FORMAT can contain the same modifiers as the entries listed in the Date_format () function.
Mysql> Select From_unixtime (Unix_timestamp (),
'%Y%d%m%h:%i:%s%x ');
-> ' 1997 23rd December 03:43:30 X '

Sec_to_time (seconds)
Returns the seconds parameter, changing to hours, minutes, and seconds, and the value is formatted as ' HH:MM:SS ' or HHMMSS, depending on whether the function is used in a string or in a numeric context.
Mysql> Select Sec_to_time (2378);
-> ' 00:39:38 '
Mysql> Select Sec_to_time (2378) + 0;
-> 3938

Time_to_sec (Time)
Returns the time parameter, converted to seconds.
Mysql> Select Time_to_sec (' 22:23:00 ');
-> 80580
Mysql> Select Time_to_sec (' 00:39:38 ');
-> 2378