I have a table package_scans with fields package_id and scan_id, and another table scan_content with scan_id and epc.

There is a 1-N relation between the tables, so for each package_scan there are multiple entries in scan_content.

I am trying to find all package scans, where there exists another scan but with all different content.

Example (for sake of simplicity all scans have exactly 2 epc, could be anywhere from 1-*):

Table package_scans:
| package_id | scan_id |
| – | — |
| 1 | 111 |
| 1 | 112 |
| 2 | 221 |
| 2 | 222 |
| 3 | 331 |

Table scan_content:
| scan_id | epc |
| – | — |
| 111 | a1 |
| 111 | a2 |
| 112 | a3 |
| 112 | a4 |
| 221 | b1 |
| 221 | b2 |
| 222 | b2 |
| 222 | b3 |
| 331 | c1 |
| 331 | c2 |

The only valid result would be package_id 1, as this package has two scans (111 and 112) with completely different epc.

Package 2 is not relevant to me, it also has two scans (221 and 222) but there is an overlap in the epc (both have b2).
Package 3 not relevant to me as it only has a single scan.

I tried with different versions of EXISTS and NOT EXISTS, but I only get to the point where I get both package_id 1 and 2 as a result, not only 1.

Here is my best approach:

SELECT package_id FROM package_scans ps1 
JOIN scan_content sc1 ON ps1.scan_id = sc1.scan_id
WHERE EXISTS (
      SELECT 1 FROM package_scans ps2
      WHERE ps1.package_id = ps2.package_id
      AND ps1.scan_id != ps2.scan_id
      AND NOT EXISTS (
            SELECT 1 FROM scan_content sc2
            WHERE ps2.scan_id = sc2.scan_id
            AND sc1.epc = sc2.epc
            )
      )

Here is my thoughts behind the my SQL:
There is a package_scan, where there exists another package_scan for the same package_id but a different scan_id. This second scan does not have a single epc that matches the epcs from the first scan.

Sadly this SQL results in both package_id 1 and 2.

Thanks in advance for any tips!