Google-sheets – Google Sheets Increase month by 1 but leave everything else the same

The code below will get all unique names from the sheet names 1 through 14 sheets and perform a summation.

Code

function getTotals() {
  var ss = SpreadsheetApp.getActiveSpreadsheet();
  var uniqueNames = [], allData = [], output = [];

  // itterate through the sheets and retrieve info  
  for(var i=1; i<14; i++) {
    this.sh = ss.getSheetByName(i); 
    this.lRow = this.sh.getMaxRows();
    this.names = this.sh.getDataRange().getValues();
    var a = this.names;

    // gather unique names and data
    for(var j=4, jLen=a.length; j<jLen; j++) {
      if(a[j][1].length > 0) {
        if(uniqueNames.indexOf(a[j][1]) == -1) {
          uniqueNames.push(a[j][1]);
        }          
        allData.push([a[j][1],a[j][2],a[j][3]]);
      }
    }    
  }

  // sort all the data for efficient processing
  var sData = allData.sort(), sNames = uniqueNames.sort();

  // itterate throught the names and perform sum
  for(var l=0, lLen=sNames.length; l<lLen; l++) {
    var sum1=0, sum2=0;
    for(var m=0, mLen=sData.length; m<mLen; m++) {
      if(sNames[l] == sData[m][0]) {
        sum1 += sData[m][1], sum2 += sData[m][2];
      }      
    }
    output.push([sNames[l], sum1, sum2]);
  }
  return output;
}

Remark

Make a copy of the spreadsheet and goto Tools>Script editor

Example

I've created a copy of your file and added the solution to it: Sum Through Sheets

As I was building this question, I figured out several ways to achieve this, so I went ahead and shared the information.

There are several ways to do this. The first is a variation on your original syntax, but using nested IF statements instead of IF and AND:

=ARRAYFORMULA(SUM(IF(MONTH($A$1:$A$5)=MONTH(E1), IF(YEAR($A$1:$A$5)=YEAR(E1), $B$1:$B$5))))

The second uses the FILTER function. This method will return a #N/A error if FILTER doesn't find any matches for the conditions. FILTER takes each condition as a separate argument:

=SUM(FILTER($B$1:$B$5, MONTH($A$1:$A$5)=MONTH(E1), YEAR($A$1:$A$5)=YEAR(E1)))

The third uses INDEX and SUMPRODUCT:

=INDEX(SUMPRODUCT((MONTH($A$2:$A$6)=MONTH(E2))*(YEAR($A$2:$A$6)=YEAR(E2))*$B$2:$B$6), 1)

In each of these examples, I assumed that the data were in columns A and B, the "pivot table" dates were in column E, and the aggregated data are placed in column F.

There might be a way to do this with the QUERY function that provides an interface to the Google Visualization API Query Language, but I'm not sure. I don't know if such a query would dynamically update, either.