How to left join two Google Sheets

If you ever tried to merge data from two different spreadsheets into one, you might have encountered problems. Maybe the process was really labor intensive, or perhaps the resulting spreadsheet was prone to breaking.

In SQL the solution to your problem would be to do a left join, but unfortunately this isn’t an integrated feature of Google Sheets. The good news? Sheetgo makes it possible to left join spreadsheets with just one click.

In this guide, we’ll explore various methods to merge two sheets, analyzing their pros and cons along the way. From manual merging to leveraging automation tools, we’ll cover it all. Finally, we’ll dive into the step-by-step process of setting up a Sheetgo connection to seamlessly combine two Google Sheets.

Are you ready to streamline your data management tasks and enhance your workflow? Let’s get started!

What’s a Left Join?

A left join is an SQL function that merges data from two different tables using columns with matching data in both tables. The term ‘join’ is pretty straightforward and denotes the action of combining data, while ‘left’ means that priority is given to fields from the left file.

Let’s look at an example of how this may be useful. Imagine you have two datasets: 

  • Newsletter sign-ups [left].
  • User metrics [right].

You want to send a newsletter to active users, but you need data from both tables to identify them effectively and there is too much data to do it manually. This is where a left join is invaluable.

To perform a left join the first step is to identify a common column between the two sheets, in this case it’s the email addresses of each user. After the join, the resulting sheet will have only users who signed up to your newsletter and all their information regarding their use of your product.

The image below exemplifies how the left file takes priority: emails that are only in the right file are excluded from the final output.

Such is the power of the left join: it enables you to bring information from different data streams into a single file for easy analysis. And what’s more important, it does so quickly and efficiently.

Left joins are only a small part of an extensive topic, if you want to learn about all the types of joins check out our article on BigQuery Joins.

Merge Google Sheets manually

There are various ways to combine two spreadsheets manually. These may be useful for smaller datasets and one-off tasks, but they grow more cumbersome and error-prone as the amount of information gets bigger.

Method 1: Good old copy-paste

This method is suitable for spreadsheets with minimal data. All you have to do is verify that the first column aligns in both sheets before copying and pasting the relevant data into a new sheet.

This is straightforward but is only useful with sheets with 10 or fewer rows. And even when this condition is met, the margin for human-error is still considerable.

Method 2:  Leveraging functions

For larger sheets, a combination of functions like IMPORTDATA and VLOOKUP can mimic a left join. The formula would look something like this:

=VLOOKUP(A1, IMPORTRANGE(“URL”, “Sheet_Name!Range”), Column_Index, FALSE)

This second method is a lot more efficient and less likely to fail. Still, you would have to iterate your spreadsheet constantly by including your formula as new rows are added. Additionally, functions are also likely to break if either sheet is modified.

As if all of this wasn’t enough, using functions can be resource-intensive, making your sheet progressively slower until it is outright unusable. And this gets worse quickly if you are planning to use other functions across other columns.

All in all, functions offer a good solution if you are working with tables that have 1000 or fewer rows and are not likely to change.

Final thoughts on manually combining sheets

As we already discussed, both of these methods have drawbacks.

Manual merging is prone to errors and becomes labor-intensive as the files grow larger.

Sheets with functions have to be updated as new rows emerge, and changes to the either sheet can potentially break the functions.

While these manual approaches offer temporary solutions, they are neither scalable nor error-proof. Therefore, they are less than ideal to work with datasets that are large or updated frequently.

Left join Google Sheets with Sheetgo

Performing a left join between two Google Sheets using Sheetgo is a straightforward process. Just follow these simple steps:

1. Create a New workflow

Left join Google Sheets 2

2. Select Create connection under “Create a custom workflow”

3. Choose Multiple files

4. Click Select file to select both of the files you want to merge

5. Go to the Next step

6. Select Left join

7. Choose the join column. This is the column that will be used as reference to match all the information. Remember that in case there are any conflicts the left file will take priority.

8. Select a destination and a file type.

9. That’s it!

You can run this new workflow whenever you want or automate it to update information periodically.

With Sheetgo, performing a left join of two Google Sheets becomes a seamless and hassle-free process, allowing you to efficiently combine data from multiple sources.

Now you can left join Google Sheets like a pro!

Armed with this step-by-step guide on how to combine Google Sheets you can streamline your data and make it easily accessible to everybody in your team. 

Sign up for Sheetgo’s free plan and start joining sheets today!

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