AW: Change detection
select Name, Department, min(year), max(year) from data group by Name, Department
The meaning of Staff_ID is obscure because it’s not unique.
Mit freundlichen Grüßen
Martin Stöcker
-----------------------------------------
ETL Datenservice GmbH
Widdersdorfer Str. 415 | D-50933 Köln
Telefon: +49(0)2219544010
Fax: +49(0)2219544015
Email: Martin.Stoecker@etl-datenservice.de 
ETL Datenservice GmbH
Widdersdorfer Str. 415 · 50933 Köln
Geschäftsführer: Dr. Dirk Goldner, ppa. Melanie Lillich, ppa. Udo Heuschmann
Amtsgericht Köln · HRB 75439 · USt.-Id: DE 122 805 685
www.etl-datenservice.de
Email: info@etl-datenservice.de
Von: Shaozhong SHI <shishaozhong@gmail.com>
Gesendet: Freitag, 9. Dezember 2022 13:55
An: pgsql-sql <pgsql-sql@lists.postgresql.org>
Betreff: Change detection
A record shows all staff member worked in different departments.
For instance, Tom was in sales for several years and got promoted to management. How to detect the time of this change?
Data
Staff_ID Name Department Year
1 Tom Sales 1990
2 Tom Sales 1991
3 Tom Sales 1991
4 Tom Management 1992
4 Tom Management 1992
Regards,
David
Вложения
В списке pgsql-sql по дате отправления: