This Google App Script will aggregate call data from CallRail on a Google Sheet. You can use Zapier to populate data about individual calls on a Google Sheet. Then use this code to aggregate the individual call data by week or month. You may need to edit the code to match your column headers.

Aggregate Spreadsheet Data By Week or Month.js

var AGGREGATION_RANGE = "month";


function updateAggregateData() {
  var dataSheetName = "Raw Data";
  var reportSheetName = "For Reports";
  
  var timeAggregatedData = new Array();
  var answeredCalls = 0;
  var notAnsweredCalls = 0;
  var totalDuration = 0;
  var averageDuration = 0;
  var totalCalls = 0;
  
  
  var spreadsheet = SpreadsheetApp.getActiveSpreadsheet();
  var rawDataSheet = spreadsheet.getSheetByName(dataSheetName);
  var reportSheet = spreadsheet.getSheetByName(reportSheetName);
  
  var rawRows = rawDataSheet.getRange(1, 1, rawDataSheet.getLastRow(), rawDataSheet.getLastColumn());
  var values = rawRows.getValues();
  
  var headers = values[0];
  for(var rowCounter = 1; rowCounter < rawDataSheet.getLastRow(); rowCounter++) {
    
    var date = new Date(values[rowCounter][0]);
    if(AGGREGATION_RANGE.toLowerCase().indexOf("month") != -1) {
      var monthIndex = date.getMonth() + 1;
      var year = date.getYear();
      var timeKey =  monthIndex + "/" + year;
    } else if(AGGREGATION_RANGE.toLowerCase().indexOf("week") != -1) {
      var weekIndex = date.getWeek();
      var year = date.getWeekYear();
      var timeKey = "week " + weekIndex + " of " + year;
    }
    
    if(!timeAggregatedData[timeKey]) {
      timeAggregatedData[timeKey] = new Object();
      timeAggregatedData[timeKey].totalCalls = 0;
      timeAggregatedData[timeKey].answeredCalls = 0;
      timeAggregatedData[timeKey].notAnsweredCalls = 0;
      timeAggregatedData[timeKey].totalDuration = 0;
      timeAggregatedData[timeKey].averageDuration = 0;
    }
    
    var thisCallDuration = 0;
      
    
    for(var columnCounter = 1; columnCounter < rawDataSheet.getLastColumn(); columnCounter++) {
      var headerName = headers[columnCounter];
      var value = values[rowCounter][columnCounter];
      
      // count total call duration
      if(headerName.toLowerCase().indexOf("duration") != -1) {
        timeAggregatedData[timeKey].totalDuration += value;
        var thisCallDuration = value;
      } 
      
      // count answered and unanswered calls
      if(headerName.toLowerCase().indexOf("answered") != -1) {
        if(value.toString().toLowerCase().indexOf("true") != -1) {
          timeAggregatedData[timeKey].answeredCalls++; 
        } else {
          timeAggregatedData[timeKey].notAnsweredCalls++;
        }
      }
      
    } // end going through all fields for each call
    
    // count total calls
    timeAggregatedData[timeKey].totalCalls++;
    
    // calculate average call duration by adding the most recent call
    timeAggregatedData[timeKey].averageDuration = ( timeAggregatedData[timeKey].averageDuration * (timeAggregatedData[timeKey].totalCalls - 1) + thisCallDuration ) / timeAggregatedData[timeKey].totalCalls;
    
  } // end going through each call
  
  
  
  
  
  // parse through time keys and generate final data sheet
  reportSheet.clear();
  reportSheet.appendRow(["Date", "Total Calls", "Answered", "Not Answered", "Total Duration (sec.)", "Avg. Duration (sec.)"]);
  for(var timeKey in timeAggregatedData) {
    var rowData = new Array();
    rowData.push(timeKey);
    for(var headerName in timeAggregatedData[timeKey]) {    
      var value = timeAggregatedData[timeKey][headerName];
      rowData.push(value);
    }
    reportSheet.appendRow(rowData);
  }
}


// UI and Trigger functions

function onOpen() {
  var ui = SpreadsheetApp.getUi();
  // Or DocumentApp or FormApp.
  ui.createMenu('Optmyzr Options')
     .addItem('Make Public', 'makePublic')
     .addSeparator()
     .addSubMenu(ui.createMenu('Time Aggregation')
          .addItem('Weekly', 'setTimeWeekly')
          .addItem('Monthly', 'setTimeMonthly'))
      .addToUi();
}

function onChange() {
  updateAggregateData();
}

function setTimeWeekly() {
  AGGREGATION_RANGE = "week";
  SpreadsheetApp.getActive().toast('Your data will now be aggregated by week', "Settings Updated", 4);
  updateAggregateData();
};

function setTimeMonthly() {
  AGGREGATION_RANGE = "month";
  SpreadsheetApp.getActive().toast('Your data will now be aggregated by month', "Settings Updated", 4);
  updateAggregateData();
};

function makePublic() {
  var id = SpreadsheetApp.getActive().getId();
  var file = DriveApp.getFileById(id);
  file.setSharing(DriveApp.Access.ANYONE_WITH_LINK, DriveApp.Permission.VIEW);
  SpreadsheetApp.getUi() // Or DocumentApp or FormApp.
     .alert('You made this file viewable by anyone with the link. This makes it available for inclusion in Optmyzr reports.');
};


// Returns the ISO week of the date.
Date.prototype.getWeek = function() {
  var date = new Date(this.getTime());
   date.setHours(0, 0, 0, 0);
  // Thursday in current week decides the year.
  date.setDate(date.getDate() + 3 - (date.getDay() + 6) % 7);
  // January 4 is always in week 1.
  var week1 = new Date(date.getFullYear(), 0, 4);
  // Adjust to Thursday in week 1 and count number of weeks from date to week1.
  return 1 + Math.round(((date.getTime() - week1.getTime()) / 86400000
                        - 3 + (week1.getDay() + 6) % 7) / 7);
}

// Returns the four-digit year corresponding to the ISO week of the date.
Date.prototype.getWeekYear = function() {
  var date = new Date(this.getTime());
  date.setDate(date.getDate() + 3 - (date.getDay() + 6) % 7);
  return date.getFullYear();
}