database - how to get current datetime in SQL?

Question

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?

Answer 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