Replicating Visitor number in Adobe Workspace with SQL for data coming through Data Feed

Hello!

I'm trying to replicate the data from Adobe Workspace based on the data we're ingesting from data feed.

Below is the code I've built:

SELECT days, COUNT(DISTINCT visitor_id)
FROM table
WHERE cid = 'campaign_code_example'
GROUP BY days
ORDER BY days ASC

 However, despite this, the numbers are different (at least 8% diff) as seen in the images below:

Adobe Workspace data:

Data collected via SQL:

Are there specific filters or amendments I need to make to the SQL code to get a near, one-to-one number?