[SalesForce] Difference between data loader and workbench

I'm going to add a little more detail here.

There's a total of four kinds of note and attachment object you might be seeing on your objects, and they're queried in different ways.

Classic Attachments

SELECT Id FROM Attachment WHERE ParentId = 'SOME_ID'

or

SELECT Id FROM Attachment WHERE Parent.Type = 'SOME_SOBJECT_TYPE'

will get you data on your old-style Attachments.

Classic Notes

These work just like Attachments, but with a different sObject:

SELECT Id FROM Note WHERE ParentId = 'SOME_ID'

or

SELECT Id FROM Note WHERE Parent.Type = 'SOME_SOBJECT_TYPE'

Content Notes and Content Documents

Content Notes are the new-style "Enhanced Notes". They're built on the Content architecture under the hood, and have rich-text bodies.

Content Documents (with associated Content Versions) represent the new Lightning Files.

Unfortunately, both are related to records using the ContentDocumentLink object, rather than having a direct lookup, and this comes with some significant query limitations:

You can't run a query without filters against ContentDocumentLink. You can't filter on ContentDocument fields if you're filtering by ContentDocumentId. You can only filter on ContentDocument fields if you're filtering by LinkedEntityId.

You can't filter on the related object fields. For example, you can't filter on the properties of the account to which a file is linked. You can filter on the properties of the file, such as the title field.

A SOQL query must filter on one of Id, ContentDocumentId, or LinkedEntityId.

So, to be short, you can't query all ContentNote or ContentDocument records attached to some specific type of object easily.

You'd have to do something like exporting all Ids for a given sObject type and iteratively querying sets of those Ids against the ContentDocumentLink table to locate attached files. This is something I've done before (and written about here), but it takes some Python or another scripting language to get it done.

If you do have a specific Id or Ids of records whose attachments you want to find, you can do it like this:

SELECT ContentDocumentId, ContentDocument.Title FROM ContentDocumentLink WHERE LinkedEntityId = 'OBJECT_ID'

Note that Content Notes are returned in a Content Document query - they are just a special type of Document.

Salesforce provides you with an option:-

Use duplicate record reports to fine-tune your duplicate and matching rules and share the results of duplicate jobs.

A duplicate records report can include these records.

• Duplicates created when a rule alerts a user to a possible duplicate, but the user creates the duplicate anyway (to generate this report, select the Report option in a duplicate rule)
• Records manually added to a duplicate record set
• Records in duplicate record sets generated by duplicate jobs

In Setup, use the Quick Find box to find Report Types.

1. Create a report type, selecting Account, Contact, Lead, or Duplicate Record Set as the primary object.
2. If you use person accounts, distinguish them from business accounts by adding the Is Person Account field in the field layout properties for your report type.
3. If you’re working toward complying with various data protection and privacy regulations, consider excluding personal data from the report name and description.
4. Click Next.
5. Relate Duplicate Record Items to the primary object that you selected. Save the report type.
6. Give your users access to the Duplicate Record Set and Duplicate Record Items objects. Then they can create reports based on the custom record type you’ve created.

Reference:- Create Reports on Duplicate Records

There is another option I found while analysing your question:-

create a custom Formula(Text) field that concatenates the fields you want to use in your duplicate criteria.

FirstName + LastName + Email, etc.

Then create a custom Formula(Number,0) field and enter 1 as the default value.

Then create a summary report grouped by your custom Text field and Summarize your custom number field, and use conditional highlighting to highlight any group with a count > 1

Reference:- How to create a Report for finding Duplicate Contacts in my instance?