Part 2: Step‑by‑Step Tutorial – Merging Google Sheets and Notion Data
Keeping your Google Sheets and Notion databases aligned can be tricky — especially when you already have some records on both sides. In this tutorial, you’ll learn how to merge existing data and set up Addsync.io to prevent duplicates in future syncs.
We’ll go through every step — from adding a connection to enabling merge settings — so you can safely sync Notion and Google Sheets.
📊 Before We Start
Here’s what our data looks like before merging:
Notion Database (Before Merge)
🧠 What We’re Doing
We’ll connect one Notion database (or table block) and one Google Sheet, then configure Addsync.io to merge records using a unique field — usually an ID, Email, or Project Name.
If both sides share the same value for that unique field, the record will be combined instead of duplicated. If no match is found, Addsync.io will create a new record based on your sync direction.
⚙️ Step-by-Step Setup
Step 2 — Choose Notion Source
Addsync will ask which type of Notion source you want to use. Select the correct option depending on your setup:
Notion Database → for a full database connection
Notion Table Block → for a page table block connection
For this tutorial we going to choose Notion Database.
Image Example:
Step 5 — Map Columns and Set Flow Direction
Tell Addsync which columns from Google Sheets should connect to which properties in Notion.
ID
ID
<->
Two-way, used for merging
Name
Name
->
From Sheets to Notion
Status
Status
<-
From Notion to Sheets
Direction Options:
→ (Sheet to Notion): Data from Google Sheets updates Notion
← (Notion to Sheet): Data from Notion updates Google Sheets
↔ (Two‑way): Data syncs both ways — whichever side updated last will overwrite the older one
You must map the column you’re using for merging, such as ID, to the same property in Notion.
After mapping, click Next.
Image Example:
Step 6 — Enable Merge and Configure Matching
From the Settings page, click the toggle to enable merge before running the first sync.
Action Steps:
Toggle “Enable merge for next sync.”
Under “Match records by”, select the unique field you decided earlier — e.g.,
ID = ID.Below that, you’ll see “Should Override” —
This checkbox controls whether Addsync should rewrite values depending on the sync direction.
Leave this enabled if you want changes from the latest update to override existing data. For this example sync setup, we’re going to enable it because Google Sheets doesn’t have the correct status values and Notion doesn’t have the correct Name values. The data will be overwritten according to the configured flow direction.
Image Example:
Step 7 — Click “Done” to Merge and Create Sync Connection
Click Done to finish setup. Addsync.io will automatically begin merging records while creating the new sync connection.
You can view the merge results directly in the Logs tab to confirm which records were updated or newly created.
Image Example:
✅ After Merging
Now your Notion database and Google Sheet are in sync — with no duplicates. Records with matching unique IDs were merged, and new rows or pages were created only when needed.
💡 Tips for Best Results
Always test on a duplicate Sheet and Notion database before syncing real data.
Use a unique field (ID, Email, etc.) for reliable merging.
If duplicate records already exist before syncing, manually delete them first; merge cannot fix pre-existing duplicates.
🎯 Summary
✨ You’re done! Your Google Sheets and Notion data are now synchronized and duplicate-free.
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