SQL NOW Vs SYSDATE Datatype
The current timestamp values are returned by MySQL's
However, the output of each of them is affected by the execution time. This makes a significant distinction between them.
SQL NOW Datatype
NOW() returns a constant time that indicates when the statement started running.
This is in contrast to the behaviour of SYSDATE ().
Example: To show how the return value might differ depending on the function used.
Select NOW(), AS 'Current date and time';
Output: The output will be
|Current date and time|
SQL SYSDATE Datatype
SYSDATE () returns the precise time of execution.
Example: Here's an example of how the return value varies based on the function you're using.
SELECT SYSDATE(), SLEEP(10) AS '', SYSDATE();
Output: The output of system which has sleep 10sec
|21-04-2022 12:37:56||0||21-04-2022 12:38:06|
Example 2: SYSDATE function
Select SYSDATE(), SLEEP(5), SYSDATE();
In comparison, the above query demonstrates that the SYSDATE() function returns the time at which it executes because it returns a value that is really incremented by 5 seconds after 5 seconds of system sleep.
Output: The output of above query is
|21-04-2022 12:41:13||0||21-04-2022 12:41:18|
SQL Difference Between NOW AND SYSDATE Statement
In below table we discuss the main contrasts in now vs sysdate fuction:-
|NOW() returns a constant time that represents the start of the statement's execution. Because NOW() is derived from the mysql variable "
||SYSDATE() returns the current time of execution.|
|The value returned by NOW() is affected by the
|NOW() returns a constant time that represents the start of the statement's execution.||SYSDATE() returns the precise time of execution.|
|NOW() will only be evaluated once, at the beginning of the query execution.||Within the same sentence, SYSDATE() is evaluated every time.|