This is my current scripting code to do cumulative total based on customer field.

// change these names to pick a view:

let table = base.getTable('Sales');

let view = table.getView('Overall');



let result = await view.selectRecordsAsync({fields: ['Customer','Sales Amount','Cumulative by Customer'],

    sorts: [

        {field: 'Customer'},

        {field: 'Sales Date', direction:'asc'},

    ]

});





let runningTotal = 0;

let currentCustomer = '';







for (let record of result.records) {

    // change the field names here to adapt this script to your base

    let currentAmount = record.getCellValue('Cumulative by Customer');

    

    // skip records

    if (currentAmount !== null) {

        continue;

    }    





console.log(record)









if (currentCustomer != record.getCellValueAsString('Customer')) {

    currentCustomer = record.getCellValueAsString('Customer');

    runningTotal = 0 ;



}

    runningTotal += record.getCellValue('Sales Amount');

     

    await table.updateRecordAsync(record, {

        'Cumulative by Customer': runningTotal,

    });

}

But now I have a problem. It doesn’t retrieve the last/previous cumulative amount record and instead it only adds current sales amount field and do the running total. How do I retrieve the last cumulative amount and add it to current running total?

Thanks.