How do you add minutes / days / months to a date in phoenix?

[#1]

Question: Are there any functions which allow date arithmetic with phoenix?

Answer: this is done as a fraction of a day. e.g. to add 12 hours to a day:

> select now(), now() + (0.5) ; 
+---------------------------------+---------------------------------+
| DATE '2017-06-04 16:55:07.989'  | DATE '2017-06-05 04:55:07.989'  |
+---------------------------------+---------------------------------+
| 2017-06-04 16:55:07.989         | 2017-06-05 04:55:07.989         |
+---------------------------------+---------------------------------+

To add 15 minutes you would use (15/1440). ie.

0: jdbc:phoenix:> select now(), now() + (0.010416666666667) ;
+---------------------------------+---------------------------------+
| DATE '2017-06-04 16:56:31.492'  | DATE '2017-06-04 17:11:31.492'  |
+---------------------------------+---------------------------------+
| 2017-06-04 16:56:31.492         | 2017-06-04 17:11:31.492         |
+---------------------------------+---------------------------------+
1 row selected (0.024 seconds)

See also: RMP-9148 "Provide Date arithmetic functions for Phoenix"