How to make an automatic timestamp in google sheets? - google-apps-script

Question

I have data in 6 columns and then a column "Last updated" where I manually write the date of the last change in the row. I am sure there is a way to automatize this, but cannot make it work.
note - I do not now how to code, just tried to modify multiple codes I found on the web and nothing worked for me, I am getting desperate.
It is basically a database of chemical substances, where each column is a property, and I need to stamp the last time any of the properties were changed. Can anyone please help me with this?

Answer 1

You will have to enter some code in order to make this work. This link gives a good example on how to create a script for your sheet.
The most important part of your script is that you want it to run EVERY time you make a change to the sheet in ANY cell. Then when it runs, you can check which cell was changed and them determine if that cell is in the area you're interested in checking. Consider a sheet set up like this one:
When you have your sheet set up, then go to the Tools menu and select Script Editor. From there you'll enter the code below. What I'm giving you is an example that you must change to meet your needs. The first part to understand is the function onEdit. This is a specially named function that will run EVERY time a change is made to the sheet. So when you have
function onEdit(eventObj) {
}
Then anything you put inside the braces will execute each time a change is made (after the user types Enter). So your onEdit function looks like this:
function onEdit(eventObj) {
//--- you could set up a dynamic named range for this area to make it easier
var thisSheet = SpreadsheetApp.getActiveSheet();
var checkRange = thisSheet.getRange("B2:D5");
if (isInRange(checkRange, eventObj.range)) {
Logger.log('cell is in range');
var propertyCell = eventObj.range;
var timestampCell = thisSheet.getRange(propertyCell.getRow(), 5);
timestampCell.setValue(Utilities.formatDate(new Date(), "UTC+8", "MM-dd-yyyy hh:mm:ss"));
} else {
Logger.log('must be outside the range');
}
The eventObj is the cell that the user edited and changed. So we are using that cell to compare with our area to check. If we determine that the cell is within that area, then we go ahead and define the cell to hold the timestamp and then assign a value to it. The value is the formatted date and time.
The important piece here is the checkRange variable that is defined as the area of all your properties. So when the onEdit function runs, it defines the area you're checking, then calls isInRange to see if the cell that was edited is within that area. Here is the function:
function isInRange(checkRange, targetCell) {
Logger.log('checking isInRange');
//--- check the target cell's row and column against the given
// checkrange area and return True if the target cell is
// inside that range
var targetRow = targetCell.getRow();
if (targetRow < checkRange.getRow() || targetRow > checkRange.getLastRow()) return false;
Logger.log('not outside the rows');
var targetColumn = targetCell.getColumn();
if (targetColumn < checkRange.getColumn() || targetColumn > checkRange.getLastColumn()) return false;
Logger.log('not outside the columns');
//--- the target cell is in the range!
return true;
}
Your result will look like this:
So now, all together, just copy and paste this code into your script editor:
function isInRange(checkRange, targetCell) {
Logger.log('checking isInRange');
//--- check the target cell's row and column against the given
// checkrange area and return True if the target cell is
// inside that range
var targetRow = targetCell.getRow();
if (targetRow < checkRange.getRow() || targetRow > checkRange.getLastRow()) return false;
Logger.log('not outside the rows');
var targetColumn = targetCell.getColumn();
if (targetColumn < checkRange.getColumn() || targetColumn > checkRange.getLastColumn()) return false;
Logger.log('not outside the columns');
//--- the target cell is in the range!
return true;
}
function onEdit(eventObj) {
//--- you could set up a dynamic named range for this area to make it easier
var thisSheet = SpreadsheetApp.getActiveSheet();
var checkRange = thisSheet.getRange("B2:D5");
if (isInRange(checkRange, eventObj.range)) {
Logger.log('cell is in range');
var propertyCell = eventObj.range;
var timestampCell = thisSheet.getRange(propertyCell.getRow(), 5);
timestampCell.setValue(Utilities.formatDate(new Date(), "UTC+8", "MM-dd-yyyy hh:mm:ss"));
} else {
Logger.log('must be outside the range');
}
}

Answer 2

It's not necessary to use scripts. It may be easier to use the formula:
=(your_datetime - date(1970;1;1) ) * 86400000
timestamp-to-date-and-back-screenshot
Check the example here: https://docs.google.com/spreadsheets/d/1JHr4z3-32fWYUAjm3bG_Wyr-ZXn7FUvrECa3B8TtJtU/edit?usp=sharing