hql date_sub

HQL (Hive Query Language) provides the `date_sub` function, which is used to subtract a specified number of days from a given date.

The syntax for the `date_sub` function in HQL is as follows:

date_sub(date, num_days)

Here, `date` is the input date from which you want to subtract days, and `num_days` is the number of days you want to subtract.

For example, to subtract 7 days from the current date, you can use the following query:

SELECT date_sub(current_date(), 7);

This will return a date that is 7 days before the current date.

Note that the `date_sub` function only works with dates and not with timestamps. If you need to subtract days from a timestamp, you can extract the date part using the `date` function and then use `date_sub`.