[SalesForce] PARENTGROUPVAL to calculate Amount Percentage in Reports

I'm afraid it will look very ugly in a summary report. While you can have up to 3 groups in it (Name + Email + Id = cool), it will be displayed as nested groups.

What you can therefore do is to create a formula field on contact (type: text) that will have FirstName + ';' + LastName + ';' + 'Email' + ';' + Id and then group by it in the report. Combine it with 'hide details" (as pointed out by @Saariko) and you're getting somewhere... Still far from ideal I'm afraid.

You should be able to do it in SOQL easily enough, maybe this would be a valid option? I have no idea how your Contacts are linked to Opportunities/Donations so I'll go through standard link. You should manage to adapt it if you have Contact__c on Opportunity or something like that.

SELECT Contact.Name, Contact.Email, ContactId, SUM(Opportunity.Amount) sum
FROM OpportunityContactRole
GROUP BY Contact.Name, Contact.Email, ContactId
LIMIT 10

(As with each aggregated query, if your organisation uses multiple currencies, these results are guaranteed to be in your corporate currency)

What if you created a Master Detail relationship between Service__c and a new object, Month__c. This new object has the Service__c field for it's parent record, and a Date field.

For every Service__c object, there exists a Month__c detail object for every month you want to count the Opportunity as "in service". Maybe the field should just be a string like '2012-12' instead of a Date datatype.

Use Batch Apex to create the initial Month__c records by iterating through all Service__c objects.

If a Service__c object is deleted for some reason, all of it's related Month__c records will go with it.

Add a trigger on Service__c to create Month__c objects for new Service__c objects or if either Contract_Start_Date__c or Date_to_Disconnect__c change.

Now you can create SOQL queries on Month__c to get the SUM of records for each month, and the total MRR. You could add one or more formula fields to represent whether the parent Service__c is a connect or disconnect in the given month, and your SOQL could include the sum of connects and disconnects.

For example, the detail records for a contract that starts in July 2012 and ends in November 2012 would look like this:

 Date      Connect  Disconnect
2012-07       1          0
2012-08       0          0
2012-09       0          0
2012-10       0          0
2012-11       0          1

It might not be the most elegant solution, since you end up with a lot of Month__c objects, but this seems like something that can't be easily calculated in a SOQL query. After the initial setup, it should be easy to maintain the Month__c objects using triggers on Service__c.