#023Level 6 of 6 · Scenario 4: Provenance
The forgery
Scenario 4 · Provenance
A specialist has written to say that one object in the collection is not what its label claims, and that the proof is in the provenance rather than in the object. A genuine chain joins up: whoever receives a piece at one step is whoever sells it at the next. A fabricated one has a party inserted to cover a gap — someone who supposedly sold the object without any record of ever having acquired it. There are 180 objects and 339 transfers on file.
Schema · 3 tables
owners
- idpkINTEGER
- nameVARCHAR
- countryVARCHAR
objects
- idpkINTEGER
- titleVARCHAR
- wingVARCHAR
- current_owner_idINTEGER
transfers
- idpkINTEGER
- object_idINTEGER
- seqINTEGER
- from_owner_idINTEGER
- to_owner_idINTEGER
- transferred_onDATE
- document_refVARCHAR
Toolkit
- SELECT
- Choose which columns come back.
- FROM
- Specify which table to read.
- WHERE
- Filter rows by a condition.
- ORDER BY
- Sort the results by a column.
- IS NULL
- Test whether a value is missing.
- INNER JOIN
- Keeps only rows that matched.
- self-join
- Join a table to itself, to compare a row with another row.
- <>
- Not equal to.
Objective
Name the party that claims to have sold an object it has no record of ever receiving.
Your query
⌘ ⏎
The party in the gap
Results
No result yet.