Re: Finding date intersections

John McKown wrote
>> insert into sales values
>>   (tstzrange('2014-1-1', '2014-1-2')),
>>   (tstzrange('2014-1-2', '2014-1-3')),
>>   (tstzrange('2014-1-2', '2014-1-4')),
>>   (tstzrange('2014-1-5', '2014-1-6'));
>>
>> -- want back:
>> --   tstzrange('2014-1-1', '2014-1-4')
>> --   tstzrange('2014-1-6', '2014-1-6')
>>

I presume the second output row should be [5,6)...

And why are you using a timestamp range when your data are dates?

My first thought is to explode the ranges into distinct dates, order them
inside a window, use lag(...) to find breaks,p and assign groups, the for
each group take the min and max of the group and form a new range.  Not sure
exactly what the SQL looks like - especially the range explosion - but
should technically work even though performance may suck. Probably want to
use lateral and generate_series(...) if you are on a more recent version.

David J.





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