1. Get the current date
select GETDATE()
format:
select CONVERT(varchar,GETDATE(),120) --2018-04-23 14:47:10
2. Get the current year --2017
select DATENAME(YYYY,GETDATE()) --2018
select DATENAME(YEAR,GETDATE()) --2018
select DATEPART(YYYY,GETDATE()) --2018
select DATEPART(YEAR,GETDATE()) --2018
select YEAR (time field name)--2018
3. Get the current month -- 05 or 5
select DATENAME(MM,GETDATE()) --04
select DATENAME(MONTH,GETDATE()) --04
select DATEPART(MM,GETDATE()) --4
select DATEPART(MONTH,GETDATE()) --4
select MONTH(time field name) --4
4. Get the current date -- 07 or 7
select DATENAME(DAY,GETDATE()) --23
select DATENAME(D,GETDATE()) --23
select DATENAME(DD,GETDATE()) --23
select DATEPART(D,GETDATE()) --23
select DATEPART(DD,GETDATE()) --23
select DATEPART(DAY,GETDATE()) --23
select DAY(GETDATE())
5. Get the current year-month-201705
select CONVERT(varchar(6),GETDATE(),112) --201804
select CONVERT(varchar(7),GETDATE(),120) --2018-04
6. Get the current year-month-day--20170512
select CONVERT(varchar(8),GETDATE(),112) --20180423
select CONVERT(varchar(10),GETDATE(),120) --2018-04-23
7. Date related functions finishing:
GETDATE() : Get the current time, the time format is the default.
DATENAME: There are two parameters, the value interval interval and time date
date is time;
interval includes year, month, day, week, etc.
eg:
YEAR year; YYYY year; YY year;
QUARTER quarter; QQ quarter; Q quarter; MONTH
month (04); MM month (04); M month (04) ; Week of the year; WK Week of the year; WW Week of the year; ISOWK Week of the year; ISOWW Week of the year; ISO_WEEK Week of the year; DAY day; DD day; D day; DAYOFYEAR day of the year; DY day of the year; Y day of the year; HOUR hours; HH hours; MINUTE minutes; MI minutes; N minutes; SECOND seconds; SS seconds; S seconds; MCS microseconds (omitted); MICROSECOND microseconds (omitted); MILLISECOND milliseconds (omitted); MS milliseconds (omitted); NANOSECOND billionths of a second (omitted); NS billionths of a second (omitted) ;
DATEPART: The parameter refers to DATENAME, but the return value is different, DATENAME returns varchar, DATEPART returns int
CONVERT function conversion format: mainly pay attention to the third parameter date_style; format: select CONVERT(varchar,GETDATE(),0)
The last date_style can have 0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22 ,23,24,25,100,
101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 120, 121, 126, 127, 130, 131, etc.
Commonly used 20, 23, 24, 102, 111, 112, 120, etc.;
Example:
select CONVERT(varchar,GETDATE(),20) --2018-04-23 14:44:22
select CONVERT(varchar,GETDATE(),23) --2018-04-23
select CONVERT(varchar,GETDATE(),24) --14:44:22
select CONVERT(varchar,GETDATE(),102) --2018.04.23
select CONVERT(varchar,GETDATE(),111) --2018/04/23
select CONVERT(varchar,GETDATE(),112) --20180423
String to date: select CONVERT(datetime,'2018-04-23',20) The third parameter refers to the above.