Not understanding mysql statement DATE_ADD(NOW() INTERVAL)

Question

I am working on a page which contains the following line of mysql. The overal objective is simply to match the current week num to the current date

$sql = "select distinct weekNum from " . DB_PREFIX . "schedule where DATE_ADD(NOW(), INTERVAL " . SERVER_TIMEZONE_OFFSET . " HOUR)"

As per my research DATE_ADD() allows you to add a certain number of days to a date.

Thus I am assuming DATE_ADD(NOW() adds the current date to...well date?

What exactly does INTERVAL do in this statment.

Any help interms of an explanation clarifying above statment will be much appreciated.

Answer 1

DATE_ADD(NOW(), INTERVAL 2 HOURS)

-- This will add 2 hours to the current time

-- The format is DATE_ADD(date, INTERVAL value unit)

value can be anything --> a number

unit will be -- > anything from following list

MICROSECOND
SECOND
MINUTE
HOUR
DAY
WEEK
MONTH
QUARTER
YEAR
SECOND_MICROSECOND
MINUTE_MICROSECOND
MINUTE_SECOND
HOUR_MICROSECOND
HOUR_SECOND
HOUR_MINUTE
DAY_MICROSECOND
DAY_SECOND
DAY_MINUTE
DAY_HOUR
YEAR_MONTH

So you can add minutes , Hours , months into your date using this function

Like that you can use the function DATE_SUB(date, INTERVAL value unit) Which will substract the date hope you are clear. for more information just visit the link [https://www.w3schools.com/sql/func_mysql_date_add.asp]