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* A function to find errors in groups in a table
@ 2022-06-09 13:37 Shaozhong SHI <[email protected]>
0 siblings, 2 replies; 5+ messages in thread
From: Shaozhong SHI @ 2022-06-09 13:37 UTC (permalink / raw)
To: pgsql-sql <[email protected]>
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?
Regards,
David
^ permalink raw reply [nested|flat] 5+ messages in thread
* A function to find errors in groups in a table
@ 2022-06-09 13:37 Shaozhong SHI <[email protected]>
parent: Shaozhong SHI <[email protected]>
1 sibling, 0 replies; 5+ messages in thread
From: Shaozhong SHI @ 2022-06-09 13:37 UTC (permalink / raw)
To: Pgsql-general <[email protected]>
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?
Regards,
David
^ permalink raw reply [nested|flat] 5+ messages in thread
* Re: A function to find errors in groups in a table
@ 2022-06-09 19:16 Steve Midgley <[email protected]>
parent: Shaozhong SHI <[email protected]>
1 sibling, 1 reply; 5+ messages in thread
From: Steve Midgley @ 2022-06-09 19:16 UTC (permalink / raw)
To: Shaozhong SHI <[email protected]>; +Cc: pgsql-sql <[email protected]>
On Thu, Jun 9, 2022 at 6:37 AM Shaozhong SHI <[email protected]> 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
^ permalink raw reply [nested|flat] 5+ messages in thread
* Re: A function to find errors in groups in a table
@ 2022-06-09 23:13 Shaozhong SHI <[email protected]>
parent: Steve Midgley <[email protected]>
0 siblings, 1 reply; 5+ messages in thread
From: Shaozhong SHI @ 2022-06-09 23:13 UTC (permalink / raw)
To: Steve Midgley <[email protected]>; +Cc: pgsql-sql <[email protected]>
The first two can be regarded right. Certainly, the last one must be
wrong. How can a primary flow get into a secondary flow?
That is odd.
Regards,
David
On Thursday, 9 June 2022, Steve Midgley <[email protected]> wrote:
>
>
> On Thu, Jun 9, 2022 at 6:37 AM Shaozhong SHI <[email protected]>
> 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
>
^ permalink raw reply [nested|flat] 5+ messages in thread
* Re: A function to find errors in groups in a table
@ 2022-06-09 23:25 Steve Midgley <[email protected]>
parent: Shaozhong SHI <[email protected]>
0 siblings, 0 replies; 5+ messages in thread
From: Steve Midgley @ 2022-06-09 23:25 UTC (permalink / raw)
To: Shaozhong SHI <[email protected]>; +Cc: pgsql-sql <[email protected]>
On Thu, Jun 9, 2022 at 4:13 PM Shaozhong SHI <[email protected]> wrote:
> The first two can be regarded right. Certainly, the last one must be
> wrong. How can a primary flow get into a secondary flow?
>
> That is odd.
>
> Regards,
>
> David
>
> On Thursday, 9 June 2022, Steve Midgley <[email protected]> wrote:
>
>>
>>
>> On Thu, Jun 9, 2022 at 6:37 AM Shaozhong SHI <[email protected]>
>> 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?
>>
>
You didn't answer my question, at least in a way I can understand, which
makes it hard to give you useful input on a solution.. Also, please try to
bottom post. This list asks posters to reply at the bottom of each email.
Steve
^ permalink raw reply [nested|flat] 5+ messages in thread
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Thread overview: 5+ messages (download: mbox mbox.gz follow: Atom feed)
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2022-06-09 13:37 A function to find errors in groups in a table Shaozhong SHI <[email protected]>
2022-06-09 13:37 ` Shaozhong SHI <[email protected]>
2022-06-09 19:16 ` Steve Midgley <[email protected]>
2022-06-09 23:13 ` Shaozhong SHI <[email protected]>
2022-06-09 23:25 ` Steve Midgley <[email protected]>
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