Re: A function to find errors in groups in a table

Поиск
Список
Период
Сортировка
От Steve Midgley
Тема Re: A function to find errors in groups in a table
Дата
Msg-id CAJexoSJ3g9W1XtdUVnss+5cw=r-ek-JSfiGUaBxCGG=BJLmHQQ@mail.gmail.com
обсуждение исходный текст
Ответ на A function to find errors in groups in a table  (Shaozhong SHI <shishaozhong@gmail.com>)
Ответы Re: A function to find errors in groups in a table
Список pgsql-sql
Дерево обсуждения


On Thu, Jun 9, 2022 at 6:37 AM Shaozhong SHI <shishaozhong@gmail.com> wrote:
There is a table full of grouped values like the following

nodeid     link_type      primary
11           outflowlink       1
11              inflowlink      1
11              outflowlink     2

Primary of 1 indicates a primary water course.  Primary of 2 indicates a secondary water course.

Obviously, one of the out flow links is an error, as its primacy value is 2.  It is wrong that water flows from a primary water course into a secondary water course.

How can a function can be designed to find and report such errors?

Is the problem that there exists this row:

11              outflowlink     2

But there is no corresponding row:

11              inflowlink     2  

So that you need to find all "orphan" rows that don't have a corresponding member with the opposing data field inflowlink or outflowlink where the "primary" column is the join field between the two rows?

Thanks for clarifying your problem,
Steve 

В списке pgsql-sql по дате отправления: