MySQL DateTime unit and expr and date_format()

(from https://dev.mysql.com/doc/refman/5.5/en/date-and-time-functions.html)

Syntax: DATE_FORMAT(date,format)

samples:
mysql> SELECT DATE_FORMAT('2007-10-04 22:23:00', '%H:%i:%s') ;
+------------------------------------------------+
| DATE_FORMAT('2007-10-04 22:23:00', '%H:%i:%s') |
+------------------------------------------------+
| 22:23:00                                       |
+------------------------------------------------+

unit Value
	
Expected expr Format
MICROSECOND/td>	
MICROSECONDS
SECOND
 
SECONDS
MINUTE
 
MINUTES
HOUR
 
HOURS
DAY
 
DAYS
WEEK
 
WEEKS
MONTH
 
MONTHS
QUARTER
 
QUARTERS
YEAR
 
YEARS
SECOND_MICROSECOND
 
'SECONDS.MICROSECONDS'
MINUTE_MICROSECOND
 
'MINUTES:SECONDS.MICROSECONDS'
MINUTE_SECOND
 
'MINUTES:SECONDS'
HOUR_MICROSECOND
 
'HOURS:MINUTES:SECONDS.MICROSECONDS'
HOUR_SECOND
 
'HOURS:MINUTES:SECONDS'
HOUR_MINUTE
 
'HOURS:MINUTES'
DAY_MICROSECOND
 
'DAYS HOURS:MINUTES:SECONDS.MICROSECONDS'
DAY_SECOND
 
'DAYS HOURS:MINUTES:SECONDS'
DAY_MINUTE
 
'DAYS HOURS:MINUTES'
DAY_HOUR
 
'DAYS HOURS'
YEAR_MONTH
 
'YEARS-MONTHS'

Specifier
	
Description
%a
	
Abbreviated weekday name (Sun..Sat)
%b
	
Abbreviated month name (Jan..Dec)
%c
	
Month, numeric (0..12)
%D
	
Day of the month with English suffix (0th, 1st, 2nd, 3rd, ...)
%d
	
Day of the month, numeric (00..31)
%e
	
Day of the month, numeric (0..31)
%f
	
Microseconds (000000..999999)
%H
	
Hour (00..23)
%h
	
Hour (01..12)
%I
	
Hour (01..12)
%i
	
Minutes, numeric (00..59)
%j
	
Day of year (001..366)
%k
	
Hour (0..23)
%l
	
Hour (1..12)
%M
	
Month name (January..December)
%m
	
Month, numeric (00..12)
%p
	
AM or PM
%r
	
Time, 12-hour (hh:mm:ss followed by AM or PM)
%S
	
Seconds (00..59)
%s
	
Seconds (00..59)
%T
	
Time, 24-hour (hh:mm:ss)
%U
	
Week (00..53), where Sunday is the first day of the week; WEEK() mode 0
%u
	
Week (00..53), where Monday is the first day of the week; WEEK() mode 1
%V
	
Week (01..53), where Sunday is the first day of the week; WEEK() mode 2; used with %X
%v
	
Week (01..53), where Monday is the first day of the week; WEEK() mode 3; used with %x
%W
	
Weekday name (Sunday..Saturday)
%w
	
Day of the week (0=Sunday..6=Saturday)
%X
	
Year for the week where Sunday is the first day of the week, numeric, four digits; used with %V
%x
	
Year for the week, where Monday is the first day of the week, numeric, four digits; used with %v
%Y
	
Year, numeric, four digits
%y
	
Year, numeric (two digits)
%%
	
A literal % character
%x
	
x, for any "x" not listed above