Príklady:

-- aktuálny dátum a cas ...
SELECT 
	GETDATE();

-- vyberieme cast z dátumu a casu ...
SELECT 
	GETDATE() AS "Aktualny datum a cas", 
	DATEPART(DAY, GETDATE()) AS "Day", 
	DATEPART(MONTH, GETDATE()) AS "Month", 
	DATEPART(YEAR, GETDATE()) AS "Year", 
	DATEPART(HOUR, GETDATE()) AS "Hour part 1.", DATEPART(hh,GETDATE()) 'Hour part 2.',
	DATEPART(MINUTE, GETDATE()) AS "Minute part 1.", DATEPART(mi,GETDATE()) 'Minute part 2.', DATEPART(n,GETDATE()) 'Minute part 3.',
	DATEPART(SECOND, GETDATE()) AS "Second part 1.", DATEPART(SS, GETDATE()) AS "Second part 2.", DATEPART(S, GETDATE()) AS "Second part 3.",
	DATEPART(millisecond,GETDATE()) 'MilliSecond Part 1.', DATEPART(ms,GETDATE()) 'MilliSecond Part 2.'

-- formátovanie dátumu a casu ...
SELECT 
	GETDATE() 'Today',
	CAST(SYSDATETIME() AS TIME) 'hh:mm:ss.nnnnnnn',
	CONVERT(VARCHAR(5), GETDATE(), 108) + (CASE WHEN DATEPART(HOUR, GETDATE()) > 12 THEN 'PM' ELSE 'AM' END) 'hh:mi AM/PM format',
	LTRIM(RIGHT(CONVERT(VARCHAR(20), GETDATE(), 100), 7)) 'hh:mi AM/PM format',
	RIGHT(CONVERT(VARCHAR(26), GETDATE(), 109),14) 'hh:mi:ss:mmmAM (or PM)',
	CONVERT(VARCHAR(12),GETDATE(),114) 'hh:mi:ss:mmm',
	CONVERT(VARCHAR(8), GETDATE(), 108) 'hh:mi:ss'
;

-- rozdiely dátumov a casov ...
SELECT DATEDIFF(year, '2005-12-31 23:59:59.9999999', '2006-01-01 00:00:00.0000000');
SELECT DATEDIFF(quarter, '2005-12-31 23:59:59.9999999', '2006-01-01 00:00:00.0000000');
SELECT DATEDIFF(month, '2005-12-31 23:59:59.9999999', '2006-03-01 00:00:00.0000000');
SELECT DATEDIFF(dayofyear, '2005-12-31 23:59:59.9999999', '2006-01-01 00:00:00.0000000');
SELECT DATEDIFF(day, '2005-12-31 23:59:59.9999999', '2006-01-01 00:00:00.0000000');
SELECT DATEDIFF(week, '2005-12-31 23:59:59.9999999', '2006-01-01 00:00:00.0000000');
SELECT DATEDIFF(hour, '2005-12-31 23:59:59.9999999', '2006-01-01 00:00:00.0000000');
SELECT DATEDIFF(minute, '2005-12-31 23:59:59.9999999', '2006-01-01 00:00:00.0000000');
SELECT DATEDIFF(second, '2005-12-31 23:59:59.9999999', '2006-01-01 00:00:00.0000000');
SELECT DATEDIFF(millisecond, '2005-12-31 23:59:59.9999999', '2006-01-01 00:00:00.0000000');

-- rôzne hodnoty a názvy z dátumu a casu ...
SELECT 
	DATENAME(year, GETDATE()) AS 'Year',
	DATENAME(month, GETDATE()) AS "Month name",
	DATENAME(day, GETDATE()) AS "Day",
	DATENAME(dayofyear, GETDATE()) AS "Day rank",
	DATENAME(quarter, GETDATE()) AS "Quarter of year",
	DATENAME(week, GETDATE()) AS "Week number of year",
	DATENAME(weekday, GETDATE()) AS "Day name"
;  

-- posúvanie dátumu a casu ...
SELECT 
	DATEADD(MINUTE, -40, GETDATE()) AS "Datum a cas pred 40 minutami",
	DATEADD(DAY, +7, GETDATE()) AS "Datum a cas o tyzden"
;

DECLARE @dt datetime2;  
SET @dt = GETDATE();  
SELECT 
	DATEADD(quarter,4,@dt) AS "Posun o 3/4 roku dopredu",
	DATEADD(month,13,@dt) AS "Posun o 13 mesiacov dopredu",  
	DATEADD(day,365,@dt) AS "Posun o 365 dni dopredu",  
	DATEADD(week,5,@dt)  AS "Posun o 5 tyzdnov dopredu",  
	DATEADD(weekday, -31,@dt) AS "Posun o 31 dni dozadu",  
	DATEADD(hour,23,@dt) AS "Posun o 23 hodin dopredu",
	DATEADD(minute,59,@dt) AS "Posun o 59 minut dopredu",
	DATEADD(second,-59,@dt) AS "Posun o 59 sekund dozadu"
;

-- zoskupovanie dátumu a casu do intervalov ...
SELECT 
	GETDATE() AS "Aktualny datum cas",
	DATEADD(MINUTE, DATEDIFF(MINUTE,0,GETDATE()) / 5 * 5, 0) AS "5min",
	DATEADD(MINUTE, DATEDIFF(MINUTE,0,GETDATE()) / 15 * 15, 0) AS "Stvrthodina",
	DATEADD(MINUTE, DATEDIFF(MINUTE,0,GETDATE()) / 30 * 30, 0) AS "Polhodina",
	DATEADD(MINUTE, DATEDIFF(MINUTE,0,GETDATE()) / 60 * 60, 0) AS "Hodina"	
;

-- praca/posúvanie s dátumu a casu trochu inak bez použitia funkcií ...
SELECT 
	GETDATE() AS "Aktualny datum cas",
	GETDATE()+1.0/(24*60*60) AS "Datum a cas o sekundu dopredu",	
	GETDATE()+1.0/(24*60) AS "Datum a cas o minutu dopredu",	
	GETDATE()-15.0/(24*60) AS "Datum a cas pred 15 minutami",		
	GETDATE()+15.0/(24*60) AS "Datum a cas o 15 minut dopredu",		
	GETDATE()+1.0/24 AS "Datum a cas o hodinu dopredu",	
	GETDATE()+1.0 AS "Zajtra o takomto case",
	GETDATE()+7.0 AS "O tyzden o takomto case"
;

Dúfam, že tieto zdrojové SQL kódy pomôžu mnohým programátorom a ušetria veľa času pri vymýšlaní a programovaní.

S pozdravom.

Alojz Bendák.