Re: Help by query - Mailing list pgsql-novice
| From | killspam killspam |
|---|---|
| Subject | Re: Help by query |
| Date | |
| Msg-id | AANLkTimz7ovnRYreRpH8+d+EN7jxnb_OQFASyr68EiNm@mail.gmail.com Whole thread Raw |
| In response to | Re: Help by query ("Oliveiros d'Azevedo Cristina" <oliveiros.cristina@marktest.pt>) |
| List | pgsql-novice |
2011/2/1 Oliveiros d'Azevedo Cristina <oliveiros.cristina@marktest.pt>
HiHowdy,Can you explain a little better the background of the problem you're trying to solve as it is not clear for me?Where did the line with id=6 come from?And what's the role of the "example number" variable you've provided ? Is it the threshold? What happens if a group surpasses it ?Best,Oliveiros----- Original Message -----From: killspam killspamSent: Tuesday, February 01, 2011 10:14 AMSubject: [NOVICE] Help by queryHello list.
I have the following problem:
Example table Origin
id | length | source | target
1 25 33 45
2 100 45 60
3 12 22 11
4 78 60 55
5 20 24 60
Example Results: new table
id | length | source | target | group | total length
1 25 33 45 1 145
2 100 45 70 1 145
3 12 22 11 3 12
4 78 60 55 2 98
5 20 24 60 2 98
6 20 30 70 1 145
Example Number variable >= 150
and I want to create groups of elements on two conditions.
source or target must match, since this indicates that touch
to group items with the first condition and that the sum of its length does not exceed a given number
not be repeated elements in groups (The items can not be processed and reprocessed)
Can someone help?
Thanks in advance
regards
Mario
Obrigado Oliveiros.
Sorry for the bad explanation.
Where did the line with id=6 come from?
The element id= 6 should be in the 2 examples.
Example table Origin
id | length | source | target
1 25 33 45
2 100 45 60
3 12 22 11
4 78 60 55
5 20 24 60
6 20 30 70
Example Results: new table
id | length | source | target | group | total length
1 25 33 45 1 145
2 100 45 70 1 145
3 12 22 11 3 12
4 78 60 55 2 98
5 20 24 60 2 98
6 20 30 70 1 145
It is only 1 table with n elements.
And what's the role of the "example number" variable you've provided ? Is it the threshold? What happens if a group surpasses it ?
- The number provided is the limit for the total of the sums of longitude that accumulate to create each group, if it exceeds the next group is created.
Explanation. :-)
1 condition: matching source or target.
2 condition: the sum of the lengths of the elements to be accumulated by the 1 st condition
can not exceed the number that would limit "the divisor" and then
when it comes next most the value of the number group closes.
and start a new one. So until there are no more records.
Each element can only belong to a group.
In a perfect world : Sum total length(all elements) / divider(limit) = number of groups
Example: 10.000 / 1000 10
Thanks in advance.
regards
Mario.
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