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Looker Studio Blend Data Tutorial (Formerly Google Data Studio)

Over the years, Looker Studio (previously known as Data Studio) has become a go-to analytical tool for thousands of businesses. It may never be as powerful as the likes of Tableau or PowerBI but its simplicity and smooth integrations with other Google products make it an appealing option for audiences of all sorts.

Like in many similar tools, there’s an option to blend data in Looker Studio too. Throughout this article, I’ll aim to show you different ways to blend data with practical examples. I’ll talk about limitations, discuss some alternatives should you need them, and answer some common questions about the Looker Studio data blend that you may also have.

What does blend data do in Looker Studio?

Blending data in Looker Studio or in another tool is about combining different sets of data. It can be data coming from different source apps (for example, aggregating stats from different advertising channels), but it’s not uncommon to be merging data from the same app too (e.g. fetching business metrics from different spreadsheets for a joint overview). 

Looker Studio data blend allows you to:

  • Easily compare data from different sources or, for example, periods of time
  • Extract valuable insights that wouldn’t be easy to spot by looking at each source separately
  • Understand the relationships between data
  • And save plenty of time you would otherwise have to spend manually blending data

Different types of data joins

To understand how data blending works, let’s first have a look at the concept of joins that are at the very base of every data blending. Joins originate from SQL language and are in common use across different languages and tools used for data processing. They determine how data should be combined – in other words, what to take from each data set.

When you blend data in Looker Studio or elsewhere, you do so on a joint dimension, commonly referred to as a join key. For example, merging data on customers from different marketing channels, you may decide on using an email address as a join key. The tool you use for blending will then combine data associated with each email address and present it to you through a joined chart or table. 

How exactly the data will be joined is determined by the join type you choose. Let’s have a look at what’s possible in Looker Studio with the help of an example.

Using, I connected my Facebook Ads and Linkedin Ads accounts to Looker Studio. Then, I aggregated the number of signups and grouped them by country. The column ‘Country’ in both datasets is my join key.

The idea is to merge the sign-up numbers from both channels so the marketing team can better understand which tool generates better results in every country. This, as a result, can help them optimize the budget, and prioritize one region over another.

1 sample dataset

In the tables above, notice that only Japan, Australia, and France are present in both datasets, while the other two countries are different in each set.

Looker Studio supports five types of joins:

  • Left (outer) join combines all data from the left table and only the data from the right table that matches the join keys present on the left. For that reason, only the countries from the Facebook Ads set were fetched. Since South Africa and Argentina don’t exist in the LinkedIn set, they return null values.
2 left join
  • Right (outer) join works in the opposite fashion to the left (outer) join. It combines all data from the right table and only the data from the left table that matches the join keys present on the right. Here, Ukraine and Brazil return null values because they don’t exist in the Facebook set. In reality, right joins are rarely used as it’s often easier to just place the main source of data on the left and go with the left join for the same effects.
3 right join
  • Inner join combines data from both tables only if a join key exists in both data sets. For that reason, only the three countries present in both sets were returned this time.
4 inner join
  • Full outer join combines all data from both tables, regardless of whether the join keys match. It can result in many nulls like in the example below but guarantees you won’t miss out on any data.
5 full outer join

Now, you must have noticed that something is wrong with the chart above – the ‘Country’ columns are repeated. Looker Studio seems to have some issues with merging these two fields when an outer join is in play, even if you have the “Hide repeated join fields” field checked in the settings. To overcome this, I used a workaround – I created a chart-specific calculated field with the following formula:

COALESCE(Country (FB data),Country (LI data))

COALESCE() here picks the first non-null values from the two columns which works perfectly for me. I hid the existing dimensions and used the calculated field instead for the following outcome:

6 coalesce applied
  • Cross join returns every possible combination of data from the left and right tables, without the need for setting a join key. In this particular context, cross join is rather useless but it can prove valuable when, for example, you compare different combinations of marketing campaigns and hope to choose the top-performing pair. Here, there were 5 rows in each column, thus 25 possible combinations (the table here would be pretty long, so I cut it a bit, but I hope you get the idea).
7 cross join

How to blend data in Looker Studio?

Now let’s talk about how Looker Studio data blend works. There are, in fact, two ways you can get started. One that’s faster but may require adjustments and another that takes a bit longer but gives you more control from the start.

Method 1 – selecting existing charts and letting Looker Studio figure out the rest

The first method is probably more intuitive, but it requires you to already have the data you want to blend on the same page – it can be, for example, two tables or line charts that you want to merge into one. To do that, select the data you want to blend and right-click on any of the charts. From the menu, select Blend data.

8 blend data option

If the option isn’t available, it means the data cannot be blended together, most likely because the chosen options aren’t compatible with each other. Here, for example, I added the labels “Facebook Ads data” and “LinkedIn Ads data” as separate text blocks and aligned them with tables. When I selected the tables, I accidentally captured also the text blocks which, obviously, can’t be blended with my advertising data. 

9 impossible to blend

If you find yourself unable to blend data this way, double-check if you didn’t capture more than you meant to. To help you determine that, you should see a descriptive error message when you hover on the disabled Blend data option (here: “text cannot be used in a blend”).

If everything went smoothly, Looker Studio will aim to figure out the right key to join the data on as well as a meaningful set of dimensions and metrics. Often, however, it doesn’t precisely return what you had in mind. You can make quick adjustments in the menu to the right or click the pencil icon next to the data source name for more advanced settings, such as changing the join type (by default, left join is used) or updating the join key. We’ll cover this next.

10 change blend settings

Method 2 – Adding a blend step by step

A more sophisticated method sits in the Looker Studio menu. Click Resource -> Manage blends. You’ll see an overview of all blends in your projects and the number of charts that use each. Choose to Add a blend.

Now, add and configure the tables you want to blend. Choose the dimensions and metrics for each. Determine the type of join that will work best for you and adjust the join conditions if you need to.

11 join configuration

It’s probably a good idea to name the blend in the top-right corner of the screen so you can easily find it later. Once you’re finished, click the Save button and close the window.

12 completing the setup

When you want to use the blended data, start adding a chart as usual. Open the data source dropdown list and find the Looker Studio data blend created earlier.

13 save the blend

Limitations of data blending in Looker Studio

Blending data in Looker Studio is absolutely possible, and many users rely on it heavily. However, there’s also a big group of users who would rather avoid this activity at all costs, as it comes with many limitations that force them to look for workarounds or even abandon certain plans. For them, blending data prior to importing it to Looker Studio is the way to go, and it’s a very viable approach too. I’ll talk about it shortly.

I’ve had a chat with a few of our analysts who work with Looker Studio on a daily basis, and here are some of the limitations that came up in these conversions:

  • Blending data makes Looker Studio slow. You may have noticed that the platform sometimes takes a fair bit of time to load your data even without blending. Things get tougher when you start blending data from different sources, especially if you choose to do so for more than two sources at a time. For each source, Looker Studio needs to connect to a different API which requires additional computing power it doesn’t always have at the moment. Blending two sources is usually fine, but the more you add,  the slower your dashboard will likely get.
  • It’s hard to verify the accuracy of blended data. When blending data in Looker Studio, all operations occur under the hood. It’s a wonderful experience, of course, for as long as everything blends as expected. Things get more problematic if your data blends with errors here or there. If you connect an app data directly to Looker Studio, you can’t usually look at the raw data to determine what causes the problem.
  • You can’t add more than 5 data sources and more than 10 dimensions from a single data source (e.g. a Google Sheets table). Both numbers may seem like a lot, but they not always are. In a typical business setup, you may sometimes need to fetch data from many different sources – for example, marketing metrics from several different apps, financial data from another, certain pieces of information from different spreadsheets, etc. When you hit either limit, you may be forced to split data into several charts or dashboards.
  • Data range filter doesn’t work for all chart types. For example, it works just fine with line charts, but if you opt to show some data on scorecards, you’re out of luck.
  • Errors of all sorts may hinder your work. Unfortunately, Looker Studio isn’t free of bugs of all sorts, and it may affect your data blending too. For example, a colleague of mine had a data source properly set up, but the connection got broken at some point – it happens. The chart using the blended data would stop working but wouldn’t display any error message. Instead, an empty table would appear, making it really difficult to figure out what the problem really is. On the other hand – while writing this article, I’ve put together some time series charts to represent how user sessions change over the course of a month. The data on charts looked fine until I chose to change the metric label on a chart. Out of nowhere, Looker Studio chose to reset the x-axis to a single day, turning my line chart into a single dot. A quick refresh would help, but it nevertheless left me wondering what just happened. This is not to say that errors appear all the time – they don’t – but it’s something to be aware of.

If you think that these limitations may make your work harder, consider some alternative approaches.

If not Looker Studio data blend, then what?

No, I don’t want to discourage you from blending data in Looker Studio. It’s a very decent feature that makes life easier, especially if your blends are rather straightforward. However, you may find it more efficient if you blend data before you connect it to Looker Studio and use the BI tool only for presenting the data.

At, we’re heavy Looker Studio users by every definition of the word. We maintain dozens of Looker Studio integrations and extensive dashboards for our own use, and the number of Looker Studio dashboards we’ve built for our clients could probably go into the thousands. Through all these experiences, we found that it’s so much easier to blend data in apps like BigQuery, Google Sheets, or directly in

Google Sheets offers native integration with Looker Studio and is commonly used as a data source. Users first import the data into their spreadsheets and then aggregate, transform, and blend it there. There are plenty of useful functions that can facilitate that, including VLOOKUP, XLOOKUP, INDEX, MATCH, etc. Once the data is prepared, they connect it to Looker Studio solely for visualization purposes which also improves the performance of their dashboards.

BigQuery also integrates directly with Looker Studio, and it’s even better for data blending if you’re familiar with some SQL. BigQuery operates with the same types of joins as Looker Studio, and you can blend two or more tables with just a simple query. Naturally, BigQuery is also more suitable for larger sets of data, such as exports of raw analytical data from your apps. is an all-in-one data analytics and integration platform. Through it, you can automate data transfers from dozens of apps you use and bring that data to Google Sheets, BigQuery, Excel, and also directly into Data Studio. If you’re not comfortable blending or visualizing data on your own, we also have a team of data experts who can help with virtually any data project you have in mind – dashboards, automated workflows, infrastructure for your data – you name it. Learn more about the service and reach out for a free consultation.

As imports the data on your behalf, it can also blend it right away so that Looker Studio focuses on what it does best – visualizations. The feature is called data stitching and the workflow is simple. 

  • You pick any number of apps or accounts to import from and decide what to import.
  • Next, you preview the dataset before it’s imported and make any necessary adjustments. You can rename columns so they match across all apps, choose to import just some of the columns, and apply filters to import only the rows matching certain criteria.
  • At your chosen frequency, importers fetch data from all chosen apps simultaneously, transform it, and bring it to the destination of your choice.
14 data blended in couplerio

Try how it works on a 14-day trial, no credit card is required.

Blending data sources in Looker Studio – frequently asked questions

I wanted now to talk about some common questions that appear among those getting started with Looker Studio data blend.

How to blend null data with a number in Looker Studio

Working with joins, you’ll quite frequently come across null values. If you choose to process these fields further, for example, to calculate outcomes in other fields, you may not get the results you were hoping for. For example, continuing with my earlier example – I used left join to blend tables with Facebook and LinkedIn signups. 

15 blending with null

Now, I want to add a column that will count the total number of signups for each country. Normally I would just create a calculated field and insert as a formula FB Sign-ups + LI Sign-ups. The outcome, however, wouldn’t be as expected. Whenever a null value appears in either of the sign-up columns, null is also returned in the totals column. 

Why? Null, by definition, indicates a missing value, not a 0 value. Since one of the values is missing, Looker Studio is unable to calculate a sum so it returns a null again.

16 failed null blending

To fix this, I need to change nulls to zeros. One approach that would seem intuitive is going to the Style settings of the blended chart and setting the Missing Data parameter to Show “0”. This will nicely swap all nulls into zeros, but it won’t change the result. Why? This setting is only suitable for making cosmetic changes. Under the hood, the values still remain null, and thus the null (0) results again.

17 show null as 0

To get the desired result, you’ll need to modify values directly in the calculated field’s formula. You can do it with NARY_MAX() function that returns a higher value of the two provided arguments. COALESCE() I used earlier would work here too. Here are the sample formulas you can use in a calculated field:

NARY_MAX(FB Sign-ups,0) + NARY_MAX(LI Sign-ups,0)


COALESCE(FB signups,0)+COALESCE(LI signups,0)

When null appears, it’s swapped for 0. And here’s the outcome:

18 fixed blend with null

How to calculate a sum of sessions in Looker Studio data blend?

As you blend data in Looker Studio, you’ll often want to sum values from different sources. For example, you may have a mobile app, and most certainly, you have a website. Perhaps you want to blend analytics from both sources and see the total number of sessions recorded every day. It’s very easy to do.

Here are sample charts demonstrating sessions recorded both in the app and on the web.

19 web and mobile sessions

To blend them and calculate the totals, select both charts and choose to blend data in Looker Studio as I did before. Then, add a new calculated field as a metric to the newly created chart with a formula that goes like this: Web sessions+App sessions. You may of course, remove the previous metrics and leave just the totals for better readability or leave all three as I did below.

20 blended sessions

How to separate data sources in a chart when blending data in Looker Studio?

What if you blended the data correctly, but you also want to see which piece of data is coming from which source? For example, by blending all the advertising data you managed to calculate the total number of signups they generated. However, now you want to see which platform is the biggest contributor to these numbers. 

To do that, you’ll need to do two things:

  • Find a suitable chart that will be able to showcase such a breakdown. For example, for a classic column chart, a stacked column chart will do the job perfectly.
  • Make sure that each of the data sources features a column indicating where the data is coming from – in other words, it’s got a field you can use to break down a chart. This is easiest to do if you connect spreadsheets or databases as you can simply add, for example, a column “Source,” and for each record in the Facebook Ads table, add… “Facebook Ads.” Repeat for all other sources you’re blending, and you’ll have an easy time separating the data.

I prepared a few sample tables where I gathered results from advertising campaigns between January and May, blending data in Looker Studio from different advertising platforms I use. Here’s the outcome in a column chart.

21 sample signups data

It’s useful, but I’m curious about which platforms contribute the most to each of these columns. So using the same dimension (Month) and metric (Sign-ups), I created a stacked column chart. Then, I added the Platform column into the Breakdown Dimension field for the following outcome:

22 stacked chart

That’s it, I´ve got both the blended data and a clear split into where each piece of data is coming from.

Why is Looker Studio blend data not working?

At times, you may find yourself confused as to why something doesn’t work in the Looker Studio data blend. General Looker Studio bugs aside, there are several common causes that may affect blending.

  • You may have misconfigured a join. As you go to the blend settings, check if you don’t see a red overlay around the join configuration that indicates an error. Make sure that every source you´re blending has a join condition set up, including the join key that matches the other keys.
23 misconfigured join
  • There may be issues with the data sources. Double-check if each source was added correctly and reconnect if needed. If the data returned after blending doesn’t quite match, hit the Refresh data button in the top-right menu and see if it changes anything.
  • Finally, the issue can be with the blending results themselves and the underlying data. Now, as I mentioned in the chapter on limitations, things get tricky when you know something is wrong but Looker Studio doesn’t really tell you what that is. When that happens, your only option is to jump into the data sources and look for the root cause. For example, if you have your data in BigQuery, blend the identical sources there and see what the outcome will be. If there are errors in your data, you should be able to isolate and fix them at this point.

As a reminder, if you need any help with your Looker Studio dashboards or any custom data projects at all, don’t hesitate to reach out to’s data team. Thanks for reading and let’s stay in touch!

  • Piotr Malek

    Technical Content Writer on who loves working with data, writing about it, and even producing videos about it. I’ve worked at startups and product companies, writing content for technical audiences of all sorts. You’ll often see me cycling🚴🏼‍♂️, backpacking around the world🌎, and playing heavy board games.

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