[SalesForce] Display an aggregate result on a visualforce page

This is untested so you may need to have play, however this should return a List of the RevenueWrapper classes which contains the 4 columns you are looking to use in your VF page:

public class RevenueController{

Map<String, RevenueWrapper> ResultList = new Map<String, RevenueWrapper>(); 

public RevenueController(){
    List<AggregateResult> result =  [
    SELECT FISCAL_YEAR(Date__c) Date, Type__c, sum(Amount__c) Amount
    FROM Revenue__c
    GROUP BY FISCAL_YEAR(Date__c), Type__c];

    for(AggregateResult ar : result){

        RevenueWrapper RW = new RevenueWrapper();

        //If the RevenueWrapper already exists grab it from the Map
        if(ResultList.containsKey(String.valueOf(ar.get('Date')))){
            RW = ResultList.get(String.valueOf(ar.get('Date')));
        }

        //Set the amount
        RW.setAmount(ar);

        //Save back to the Map
        ResultList.put(String.valueOf(ar.get('Date')), RW);
    }
}

public List<RevenueWrapper> getResults() {
    return ResultList.values();
}


public class RevenueWrapper{
    public String revenueDate { get; set; }
    public Integer budgetAmount { get; set; }
    public Integer actualAmount { get; set; }
    public Integer varianceFYPercent { set; }
    public Integer varianceFYAmount { set; }

    public RevenueWrapper(){

    }

    public void setAmount(AggregateResult ar){
        revenueDate = String.valueOf(ar.get('Date'));

            //Set the amount value based on type
        if(ar.get('Type__c') == 'Budget'){
            budgetAmount = Integer.valueOf(ar.get('Amount'));
        }else if(ar.get('Type__c') == 'Actual'){
            actualAmount = Integer.valueOf(ar.get('Amount'));
        }else{ //Catch all for a type that isn't recognised
            return;
        }

    }

    public Integer getVarianceFYAmount(){
        return actualAmount - budgetAmount;
    }

    public Decimal getVarianceFYPercent(){
        if(budgetAmount != 0){
            return Decimal.valueOf((Double.valueOf(actualAmount) / Double.valueOf(budgetAmount)) * 100).setscale(1);
        } else{
            return 0;
        }
    }
}

}

First fine-tune your query so you get the results you're happy with. If you want the split per iteration - probably something like this:

SELECT Iteration__r.Name iName, SUM(duration__c) sumDuration
FROM Time_Entry__c
WHERE User__c = :UserInfo.getUserId()
GROUP BY ROLLUP(Iteration__r.Name)

1. Eclipse IDE might behave funny when it comes to aggregate queries. Consider using the Workbench, RealForceExplorer or another tool if you'll see columns that appear to be blank.
2. ROLLUP word is useful if you want to get a grand total row at the bottom. If you don't need it - go with simple GROUP BY Iteration__r.Name
3. Add more fields as you see fit. Roughly speaking every field you'll add to main SELECT you'll also have to add to GROUP BY clause.

Once you're happy create a wrapper class, I'd go with

public class Wrapper{
    public Decimal duration {get; private set;}
    String iterationName {get; private set;}

    // Constructor
    public Wrapper(AggregateResult ar){
        duration = Decimal.valueOf(ar.get('sumDuration'));
        iterationName = String.valueOf(ar.get('iName'));
    }
}

And then simply loop through the results like you had system.debugs but keep adding Wrappers to a list:

List<Wrapper> wrappers = new List<Wrapper>(); // should be a publicly available variable so either declare it at class level or provide a getter ;)
for (AggregateResult ar: iterationResults) {
    wrappers.add(new Wrapper(ar));
}

Edit (re: comment about recalculating the list of wrappers on save)

Roughly speaking you have 2 options:

1. Stick the code that queries & recalculates the wrappers (preferably a call to helper function) at the end of the method that's being called when you hit save button. This gets bit more interesting if you were using the {!save} from standard controller, let me know.

2. Useful especially if it's a throwaway thing - you use this List<Wrapper> only to display it on VF and nowhere else - delete the class variable with the list and create a getter function instead. That way it'll be taken fresh every time VF "gets" the values:

   public List<Wrapper> getWrappers(){
       List<Wrapper> temp = new List<Wrapper>();
       // query here...
       return temp;
   }