使用GROUP BY的核心数据获取请求

Question

I have a table in my application which consists of some names and phone numbers and orderIDs and dates (4 columns). I want to get an array of all distinct phone numbers (Note that someone with a phone number may have several orderIDs).

Test case: suppose that this is the current records of my table.

Name phoneNumber orderID date John 1234 101 2014-12-12 Susan 9876 102 2014-12-08 John 1234 103 2014-12-17

I want an array of distinct phone numbers only, something like: {1234, 9876} How can I perform such a fetch in core data?

Any help would be much appreciated. Thank you.

PS: As I knew in SQL I could do something like:

SELECT phoneNumber FROM orders GROUP BY phoneNumber

Answer 1

You can use Distinct Keyword. so your query will become

SELECT DISTINCT phoneNumber FROM orders