Re: Split daterange into sub periods

On 07/05/2018 06:49 AM, hmidi slim wrote:
> Hi,
> I'm looking for splitting a daterange into many subperiods following
> this example:
>
> Base Date: [2018-01-01, 2018-01-31]
> overlapped_periods:
> 1- [ 2018-01-04, 2018-01-06]
> 2- [ 2018-01-09, 2018-01-12]
> 3- [ 2018-01-18, 2018-01-19]

Overlapping what?
They are not overlapping each other.

>
> I try to get such a result:
> 1- [ 2018-01-01, 2018-01-03]
> 2- [ 2018-01-07, 2018-01-08]
> 3- [ 2018-01-13, 2018-01-17]
> 4- [ 2018-01-20, 2018-01-31]

Not sure what the above represents.
Are you looking for the dates in the range [2018-01-01, 2018-01-31] that
are not in the 3 sub-ranges at the top of the post?

>
> The operator '-' does not support this :
>
> SELECT daterange('2018-01-01', '2018-01-31', '[]') -
> daterange('2018-01-04', '2018-01-06', '[]');
>
> I got this error:
>
> *ERROR: result of range difference would not be contiguous

That is expected:

https://www.postgresql.org/docs/10/static/functions-range.html

"The union and difference operators will fail if the resulting range
would need to contain two disjoint sub-ranges, as such a range cannot be
represented."

>
> *
>
> Is there any operators to make the split of daterange?*
> *

Not that I know of.

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--
Adrian Klaver
adrian(dot)klaver(at)aklaver(dot)com