Question

There are two databases and 4 tables involved in this query. The first database(PhoneBills) contains the first table(CallDetails), and within this there are columns for :

1. [Time] (start time)
2. [From] (caller number)
3. [To] (target number)
4. [Cost] (in money)
5. [Length] (how long called)

The columns of interest here are [From] and [To].

In the second database(rtc – this is a Lync persistent data DB) there are three tables of interest :

1. Resource (matches ResourceID to Username)
2. ResourceDirectory (defines the Time a ResourceID was Inserted and when it was last Updated)
3. ResourcePhone (matches a ResouceID to a phonenumber)

I don’t honestly know what ResourceDirectory defines, I am guessing that the phone numbers that usernames are matched to can change, and the directory keeps track of those times. For the purposes of simplification, I will ignore this part for now.

What I am trying to achieve is to get the Username from Resource given that I can find a match for my phone number in ResourcePhone.

Answer 1

Won’t this work?

SELECT Username
FROM Resource R
JOIN ResourcePhone RP on R.ResourceID = RP.ResourceID
WHERE RP.phonenumber = '1111111111'