Re: Divide table raw into chunks

I not sure but proably with a recursive CTE (common table expression)

somethink like

with R as (
select send_id, 4 as len, 1 as chunk
, substring(bow from 1 for 4) as bow_ok, substring (bow for 4 +1) as
bow_2
from bow1
union all
select send_id, len, chunk+1 as chunk
, substring(bow_2 from 1 for 4) as bow_ok, substring (bow from 4 +1)
as bow_2
where char_length((bow_2) >0
from R
)
select * from r

www.postgresql.org/docs/9.3/static/queries-with.html

2016-02-28 5:39 GMT-06:00 Shmagi Kavtaradze <kavtaradze(dot)s(at)gmail(dot)com>:

> I have a table with too long entries with 1s and 0s. For example I have
> table :
>
> | Sent id.| BoW. ||---------|----------|| 1 | 10100101 || 2 | 00011110 || 3 | 10101111 |
>
> I want to create new table which will divide column BoW. entries into some
> arbitrary length and assigns chunk number.
>
> | Sent id.| Chunk No. | BoW. ||---------|-----------|------|| 1 | 1 | 1010 || 1 | 2 | 0101 || 2 | 1 | 0001 || 2 | 2 | 1110 || 3 | 1 | 1010 || 3 | 2 | 1111 |
>
> I am beginner, tried to search in documentation, but without success.
> Maybe something like this, but with proper function:
>
> select b.sent_id, chunk, substring(bow from (chunk - 1) * 4 + 1 for 4)from (select b.sent_id, generate_series(1, 1 + floor(length(bow) - 1 / 4) ) as chunk
> from bow1 b
> ) b;
>
>
> I have 4623 Sent ids (sentences) and each is 10,000 characters long. I
> want to divide them into 32-40 character long chunks.
>
>

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