Combining data in Looker Studio means joining two or more data sources within the same report to analyze metrics from different platforms in a single view. This feature, called “Data Blending” or “Join Data,” lets you cross-reference information from Google Ads, GA4, spreadsheets, Meta Ads, and other sources using a common field. For digital marketing agencies managing multiple client accounts, mastering this technique reduces analysis time and eliminates the need to export data manually.
What is combining data in Looker Studio and what is it for?
Looker Studio (formerly Google Data Studio) offers a native feature for blending data sources within the same chart or table. Instead of creating separate reports per platform, you can cross metrics from different origins and get a unified view of your campaigns’ performance.
This feature is especially useful in the following cases:
- Comparing Google Ads ad spend with conversions recorded in GA4
- Cross-referencing Meta Ads data with eCommerce sales results
- Joining metrics from different paid platforms into a consolidated performance table
- Combining CRM data with email marketing campaign metrics
- Generating dashboards for clients who invest in multiple channels simultaneously
For digital marketing agencies, account directors, and performance managers, this ability to join data reduces manual work and improves the quality of the reports delivered to clients.
Prerequisites for combining data in Looker Studio
Compatible data sources
Looker Studio supports native and third-party connectors. Before joining data, you must connect each source independently. The most commonly used by agencies are:
| Data source | Connector type | Requires authentication |
|---|---|---|
| Google Ads | Native | Yes, Google account |
| Google Analytics 4 | Native | Yes, Google account |
| Google Sheets | Native | Yes, Google account |
| Meta Ads | Third-party connector | Yes, access token |
| LinkedIn Ads | Third-party connector | Yes, access token |
| TikTok Ads | Third-party connector | Yes, access token |
| BigQuery | Native | Yes, GCP project |
Join key field
The join field is the element that connects both sources. It must exist in all the sources you want to combine. The most common fields are:
- Date: useful for comparing daily performance across platforms
- Campaign ID: allows cross-referencing spend data with conversions at the campaign level
- Customer ID: used to join CRM data with advertising metrics
- Country or region: facilitates multi-source geographic analysis
Types of data joins available in Looker Studio
Left outer join
Includes all records from the primary source and matching records from the secondary source. If there is no match, the secondary field appears empty. This is the most commonly used join type in agency reports.
Inner join
Only includes records that have a match in both sources. Produces cleaner data sets, but may exclude valid data if the tables don’t match perfectly.
Right outer join and full outer join
Less common in marketing reports. The right outer join prioritizes the secondary source. The full outer join includes all records from both sources, regardless of whether there is a match.
Cross join
Combines every row from one source with every row from the other. Generates very large tables. Used only in very specific combinatorial analysis cases.
How to combine data in Looker Studio step by step
- Open or create a report in Looker Studio. If starting from scratch, click “Create” and select “Report.”
- Connect the first data source. In the side panel, select “Add data” and choose the corresponding connector. Authenticate if the system prompts you.
- Connect the second data source following the same process. Both sources must be active in the report before joining them.
- Select a chart or table on the report canvas. In the data panel, look for the “Data source” section and click the blend icon or “Blend data.”
- Access the data blending editor. Looker Studio opens a window where you can select the sources you want to join.
- Define the join key field. Select the field shared by both sources, for example, “Date” or “Campaign ID.”
- Choose the join type: left outer join, inner join, right outer join, full outer join, or cross join depending on your use case.
- Select the dimensions and metrics you want to include in the combined data set. You can choose fields from both sources.
- Save the blend and return to the canvas. The chart or table now shows data from both sources unified.
- Review the results. Verify that the values match the original data from each platform. If there are discrepancies, check the join field.
Combining data in Looker Studio vs. alternatives
| Criteria | Looker Studio | Supermetrics | Master Metrics |
|---|---|---|---|
| Cost | Free | From ~$99/month | Agency plans |
| Initial setup | Medium-high | Medium | Low (ready-made dashboards) |
| Native connectors | Limited to Google | Wide variety | Meta, Google, LinkedIn, TikTok, GA4 |
| Source blending | Manual, per chart | Requires setup | Automatic and centralized |
| Data refresh | Manual or scheduled | Scheduled | Automatic in real time |
| Learning curve | High for complex blends | Medium | Low |
| Ideal for | Technical analysts | Data teams | Digital marketing agencies |
Looker Studio is a valid option when the team has the technical capacity to set up blends and maintain them. However, for agencies managing multiple clients, tools like Master Metrics automatically centralize data from all platforms, with no need to manually configure joins for each client or each report.
Common mistakes when combining data in Looker Studio
Join field with different formats
If the “Date” field in one source uses the YYYY-MM-DD format and another uses DD/MM/YYYY, the join won’t find matches. Standardize the format before combining.
Metric duplication
When performing a full outer join or a cross join without the correct field, data can multiply. Always check the totals against the original source.
Calculated fields that don’t carry over
Calculated fields from a data source aren’t always available in the blend. In that case, recreate the calculation directly in the blend editor.
Limit on sources per blend
Looker Studio allows combining up to 5 data sources in a single blend. If you need more, you must create nested blends or use an intermediate source such as Google Sheets or BigQuery.
Frequently asked questions about combining data in Looker Studio
How many data sources can I combine in a single Looker Studio report?
You can connect a large number of sources to the same report, but each individual blend has a limit of 5 sources. If you need to cross more than 5 origins, the most common solution is to first consolidate data in Google Sheets or BigQuery and then connect that unified source to Looker Studio.
Does data blending in Looker Studio affect report performance?
Yes. Complex blends with multiple sources and large data volumes can slow down report loading. To mitigate this, apply date filters, reduce the number of fields in the blend, and avoid using cross join unless strictly necessary.
Can I combine Meta Ads data with Google Ads in Looker Studio natively?
Not entirely natively. Meta Ads doesn’t have a native connector in Looker Studio, so you need a third-party connector such as Supermetrics, Porter Metrics, or to export the data to Google Sheets. This adds extra steps and can generate additional costs for connector licenses.
Does the data blend update automatically?
Blended data updates according to the frequency configured for each individual data source. If one source updates daily and another updates hourly, the blend will only show data as fresh as the slowest source allows. There is no native real-time update for all sources.
What’s the difference between “combining data” and “blending sources” in Looker Studio?
“Combining data” (data blending) is Looker Studio’s official term for joining two or more data sources through a common field. “Blending sources” is an informal description of the same process. Both terms refer to the same functionality within the platform.
Is it hard to maintain data blends when source structures change?
Yes, this is one of the main friction points. If a platform renames a column or removes a field, the blend stops working and must be manually reconfigured. For agencies with many clients, this represents a significant operational cost that recurs every time there are changes to the platforms’ APIs.
How does Master Metrics help solve the problems of combining data from multiple platforms?
Master Metrics automatically centralizes data from Meta Ads, Google Ads, LinkedIn Ads, TikTok Ads, GA4, and other platforms into a unified dashboard, with no need to configure manual blends in Looker Studio. Data updates automatically, and the system is designed for agencies managing multiple client accounts, eliminating the time spent maintaining integrations and allowing teams to focus on analysis and strategy.
Conclusion
Combining data in Looker Studio is a valuable technical skill for any digital marketing team. It allows you to unify metrics from different platforms, build more complete reports, and make decisions with a real view of each channel’s performance. However, manual setup, limits on sources per blend, and reliance on third-party connectors for platforms like Meta Ads represent real friction for agencies operating at scale.
The more clients an agency manages, the more time it takes to keep these integrations updated. Every API change, every new client, or every campaign on an additional platform means reconfiguring blends and verifying that the data remains accurate. That operational time has a direct cost on the team’s profitability.
If your agency is looking to centralize data from multiple platforms without relying on manual configurations, Master Metrics offers automated dashboards with all integrations already built. You can connect your accounts, share reports with clients, and focus on what truly generates value: analysis and strategy.
