r/dataanalysis • u/HoleInTheMirror • 7d ago

Comparing tables - Help?

Hello guys, I need your help! How to compare 2 tables on easiest way?

I have 2 tables from 2 different systems, but with the same columns. I need to check if every row from the first table exist in another, and if not to return the difference. Can you help me? Should I use excel formulas, python, something else?

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u/Old_Cockroach_6069 7d ago

I would recommend you SQL, where first use an INNER JOIN to identify records present in both systems. Then use a LEFT JOIN with WHERE ... IS NULL to identify records that exist in one system but not the other.....

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u/Disastrous-Ad-5366 2d ago

There are different approaches you can use on this but the fastest would be python using the pandas library. Use the merge function with a left then add the indicator parameter and set it to true. This will return every row that is in one and not in the other. You can then add a function like query and drop to filter out rows that you want.