Merging Old UA Data with GA4 Data on a Same Chart

Accessing Universal Analytics data is now impossible. The interface shows no data or API requests with other tools return no result. So, I hope you already did back-up of your UA data in somewhere else such as BigQuery, Google Sheets, Data warehouse etc. In this article, I will be assuming that you have UA data in Google Sheets. I will show you to merge 2022-2023 data from UA with 2024 YTD GA4 data in Looker Studio chart. Let’s begin quickly.

My 2022-2023 UA data in Google Sheets is like this below. It is important to keep ultimate date column in a format as YY-MM-DD, Looker Studio knows this date format by default. That’s why I have “date updated” column.

Now, it is time to work on Looker. Firstly, please add GA4 and Universal Analytics data sources to the report. Then, go Resource -> Manage added data sources -> Edit UA data. Then, duplicate date dimension two times. Adjust one of them to be Year and the other one to be Month. Save it. So, dimensions will look like this:

Let’s create our time series chart now. As a source of chart, we need to use blend. Create blended data and adjust the fields like this:

GA4 is only responsible for 2024 data in this case, that’s why date range filter is applied to this year. When you are done with blended source configurations, it is now time to adjust time series chart fields. For metrics, we have options of Sessions (Table 1) and Sessions (Table 2). However, we need to use BOTH. So, we are going to create new field in order to include both tables’ Sessions. Apply this formula in new metric field, data type should be number:

CASE
  WHEN Sessions (Table 1) IS NOT NULL THEN Sessions (Table 1)
  ELSE Sessions (Table 2)
END

Also, for dimension we need not only Month (Table1) or Table 2, but unified month dimension. To do that, also use this formula in a new field. Make it sure that data type is Month:

CASE 
  WHEN Month (Table 1) IS NOT NULL THEN Month (Table 1)
  ELSE Month (Table 2)
END

Again, for the breakdown dimension, create a unified Year field and use this formula, make sure data type is Year:

CASE
  WHEN Year (Table 1) IS NOT NULL THEN Year (Table 1)
  ELSE Year (Table 2)
END

After you configure everything correctly and make visualization settings, final chart will look like this:

To sum up, this article aims to show you the possibility of old Universal Analytics data to current GA4 set up in Looker Studio. Some companies migrated to GA4 on late 2023s. So, when you prepare a dashboard, your clients might want to see past numbers too. I hope this blog post would help you to understand merging different data sources.