Function

NOW

Returns current date and time

SELECT 
    NOW()

Function

UNIX_TIMESTAMP

returns seconds since

1970-01-01 00:00:00

UTC

SELECT 
    UNIX_TIMESTAMP()

If any date is passed to the function as a parameter, it will calculate seconds since

1970-01-01 00:00:00

to the passed date. In this example, the function returns seconds to

2021-03-25

SELECT 
    UNIX_TIMESTAMP('2021-03-25')

Function

SYSDATE

Returns current date and time

SELECT 
    SYSDATE()

We can pass parameter

precision

to the function that indicates milliseconds and microseconds:

SELECT 
    SYSDATE(6)

Function

CURRENT_DATE

returns current date with the following syntax:

YYYY-MM-DD

SELECT 
    CURRENT_DATE()

Function

CURDATE

returns current date with the following syntax:

YYYY-MM-DD

SELECT 
    CURDATE()

Function

ADDDATE

adds some amount of time to the specified date

SELECT 
    ADDDATE('2021-03-25', INTERVAL 8 DAY)

Function

SUBDATE

subtracts some amount of time from the specified date

SELECT 
    SUBDATE('2021-03-25', INTERVAL 30 DAY)

Function

DATEDIFF

Calculates the number of days between the two parameters. In this example the function returns

12

which is the number of days between the dates

SELECT 
    DATEDIFF('2021-03-25', '2021-03-13')

The function returns

negative number

if the second date is greater than the first one. In the example the result will be

-12

SELECT 
    DATEDIFF('2021-03-13', '2021-03-25')

Function

TIMESTAMPDIFF

calculates the difference between two times. The result is in unites that we want to measure the difference between the times

SELECT 
    TIMESTAMPDIFF(DAY, '2021-03-13', '2021-03-25')

Function

MAKETIME

takes three parameters as hour, minute and time and returns formatted time like:

18:15:19

SELECT 
    MAKETIME(18, 15, 19)

Function

LAST_DAY

takes date and returns the last date of the month. In the example the result is

28

because the year is not leap year

SELECT 
    LAST_DAY('2021-02-15')

Function

DATE_FORMAT

returns formatted version of the datetime string passed as the first parameter

SELECT 
    DATE_FORMAT('2022-03-25 18:24:14', '%Y-%m-%d %H:%i:%s')

In this example we only need to get month and day with underscore between the values

SELECT 
    DATE_FORMAT('2022-03-25 18:24:14', '%m_%d')