日期和時間函數主要用來處理日期和時間值，本篇主要介紹各種日期和時間函數的功能和用法，一般的日期函數除了使用date類型的參數外，也可以使用datetime類型的參數，但會忽略這些值的時間部分。相同的，以time類型值為參數的函數，可以接受datetime類型的參數，但會忽略日期部分。

 getDate()函數用于返回當前數據庫系統的日期和時間，返回值的類型為datetime.【例】select getDate() as currentTime;

 UTCDATE()函數返回當前UTC(世界標準時間)日期值.【例】select GETUTCDATE() AS UTCtime;

 因為本人深處朝廷管轄范圍之內，位于東八時區，所以系統的當前時間比UTC提前8小時，所以這里顯示的UTC時間需要減去8個小時的時差。

 DAY(d)函數用于返回指定日期的d是一個月中的第幾天，范圍從1~31，該函數在功能上等價于DATEPART(dd,d)。【例】select DAY('2015-04-30 01:01:01');

 MONTH(d)函數用于返回指定日期d中月份的整數值?！纠縎ELECT MONTH('2015-04-30') AS monthValue; 

 YEAR(d)函數返回指定日期d中年份的整數值?！纠縎ELECT YEAR('2015-04-30'),YEAR(1997-07-01);

 DATENAME(dp,d)根據dp指定返回日期中相應部分的值，例如YEAR返回日期中的年份值，MONTH返回日期中的月份值，dp其它可以取的值有:quater,dayofyear,day,week,weekday,hour,minute,second等?！纠縎ELECT DATENAME(year,'2015-04-30 01:01:01') AS yearValue;   SELECT DATENAME(quater,'2015-04-30 01:01:01') AS quaterValue;   SELECT DATENAME(dayofyear,'2015-04-30 01:01:01') AS dayofyearValue;   SELECT DATENAME(day,'2015-04-30 01:01:01') AS dayValue;   SELECT DATENAME(week,'2015-04-30 01:01:01') AS weekValue;   SELECT DATENAME(weekday,'2015-04-30 01:01:01') AS weekdayValue;   SELECT DATENAME(hour,'2015-04-30 01:01:01') AS hourValue;   SELECT DATENAME(minute,'2015-04-30 01:01:01') AS minuteValue;   SELECT DATENAME(second,'2015-04-30 01:01:01') AS secondValue;

 DATEPART(dp,d)函數返回指定日期中相應的部分的整數值，dp的取值與DATETIME函數相同?！纠縎ELECT DATEPART(year,'2015-04-30 01:01:01'),DATEPART(month,'2015-04-30 01:01:01'),       DATEPART(dayofyear,'2015-04-30 01:01:01');

 DATEADD(dp,num,d)函數用于執行日期的加運算，返回指定日期值加上一個時間段后的新日期。dp指定日期中進行加法運算的部分值，例如：year，month,day,hour,minute,second,millsecond等，num指定與dp相加的值，如果該值為非整數值，將舍棄該值的小數部分，d為執行加法運算的日期。 SELECT DATEADD(year,1,'2015-04-30 01:01:01') AS yearAdd, DATETIME(month ,2, '2015-04-30 01:01:01') AS weekdayAdd, DATEADD(hour,2,'2015-04-30 01:01:01') AS hourAdd;

日期函數上面例子的腳本：

-時間函數select  getDate() as currentTime;select  GETUTCDATE() AS UTCtime;select  DAY('2015-04-30 01:01:01');SELECT  MONTH('2015-04-30')AS monthValue;SELECT  YEAR('2015-04-30'),YEAR('1997-07-01');SELECT DATENAME(year,'2015-04-30 01:01:01') AS yearValue,       DATENAME(quarter,'2015-04-30 01:01:01') AS quaterValue,       DATENAME(dayofyear,'2015-04-30 01:01:01') AS dayofyearValue,       DATENAME(day,'2015-04-30 01:01:01') AS dayValue,       DATENAME(week,'2015-04-30 01:01:01') AS weekValue,       DATENAME(weekday,'2015-04-30 01:01:01') AS weekdayValue,       DATENAME(hour,'2015-04-30 01:01:01') AS hourValue,       DATENAME(minute,'2015-04-30 01:01:01') AS minuteValue,       DATENAME(second,'2015-04-30 01:01:01') AS secondValue; SELECT  DATEPART(year,'2015-04-30 01:01:01'),        DATEPART(month,'2015-04-30 01:01:01'),        DATEPART(dayofyear,'2015-04-30 01:01:01');        SELECT    DATEADD(year,1,'2015-04-30 01:01:01') AS yearAdd,        DATEADD(month ,2, '2015-04-30 01:01:01') AS weekdayAdd,        DATEADD(hour,2,'2015-04-30 01:01:01') AS hourAdd;