how to get current datetime in SQL?

问题:

Want to get current datetime to insert into lastModifiedTime column. I am using MySQL database. My questions are:

1. is there a function available in SQL? or

2. it is implementation depended so each database has its own function for this?

3. what is the function available in MySQL?

回答1:

Complete answer:

1. Is there a function available in SQL?
Yes, the SQL 92 spec, Oct 97, pg. 171, section 6.16 specifies this functions:

CURRENT_TIME       Time of day at moment of evaluation
CURRENT_DATE       Date at moment of evaluation
CURRENT_TIMESTAMP  Date & Time at moment of evaluation

2. It is implementation depended so each database has its own function for this?
Each database has its own implementations, but they have to implement the three function above if they comply with the SQL 92 specification (but depends on the version of the spec)

3. What is the function available in MySQL?

NOW() returns 2009-08-05 15:13:00  
CURDATE() returns 2009-08-05  
CURTIME() returns 15:13:00  

(As SixFootTallRabbit says)

回答2:

I always just use NOW():

INSERT INTO table (lastModifiedTime) VALUES (NOW())

http://dev.mysql.com/doc/refman/5.1/en/date-and-time-functions.html#function_now

回答3:

NOW() returns 2009-08-05 15:13:00

CURDATE() returns 2009-08-05

CURTIME() returns 15:13:00

回答4:

I want my datetime, and I want it now()!

For MySQL, anyway.

回答5:

For SQL Server use GetDate() or current_timestamp. You can format the result with the Convert(dataType,value,format). Tag your question with the correct Database Server.

回答6:

SYSDATETIME() 2007-04-30 13:10:02.0474381
SYSDATETIMEOFFSET()2007-04-30 13:10:02.0474381 -07:00
SYSUTCDATETIME() 2007-04-30 20:10:02.0474381
CURRENT_TIMESTAMP 2007-04-30 13:10:02.047 +
GETDATE() 2007-04-30 13:10:02.047 
GETUTCDATE() 2007-04-30 20:10:02.047

I guess NOW() doesn't work sometime and gives error 'NOW' is not a recognized built-in function name.

Hope it helps!!! Thank You. https://docs.microsoft.com/en-us/sql/t-sql/functions/getdate-transact-sql

回答7:

1. GETDATE() or GETUTCDATE() are now superseded by the richer SYSDATETIME, SYSUTCDATETIME, and SYSDATETIMEOFFSET (in SQL 2008)
2. Yes, I don't think ANSI has ever declared anything, and so each manufacturer has their own.
3. That would be NOW()

Hope this helps...

Rob