@AJ Welcome to Microsoft Q&A forum and thanks for reaching out here.
To achieve your requirement, you can use checksums and hash a row fingerprint to filter out the source data based on specific columns.
Related docs: Mapping data flow functions
Here is detailed demonstration of similar use case scenario from ADF product team: ADF: Detect source data changes in Data Flows
Hope this info helps. In case if you have already tried it and having any issues or if your requirement is different than what has been discussed in the demonstration, kindly share few additional details (like sample dummy data for testing) so that we can assist accordingly.
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