How to find the first consecutive days of a dataset in SQL? - presto

Question

Im trying to select only the first consecutive dates in SQL from the table
The final results should look like this
This is the example of the initial table.
This is the initial table I have.
> Campaign Code Current Date Campaign Start Date Days Since Campaign
> Launch Next DaTe Next date - Current Date domestic campaign
> 1 10/01/2022 10/01/2022 0 11/01/2022 1 domestic campaign
> 1 11/01/2022 10/01/2022 1 12/01/2022 1 domestic campaign
> 1 12/01/2022 10/01/2022 2 13/01/2022 1 domestic campaign
> 1 13/01/2022 10/01/2022 3 14/01/2022 1 domestic campaign
> 1 14/01/2022 10/01/2022 4 15/01/2022 1 domestic campaign
> 1 15/01/2022 10/01/2022 5 16/01/2022 1 domestic campaign
> 1 16/01/2022 10/01/2022 6 17/01/2022 1 domestic campaign
> 1 17/01/2022 10/01/2022 7 18/01/2022 1 domestic campaign
> 1 18/01/2022 10/01/2022 8 19/01/2022 1 domestic campaign
> 1 19/01/2022 10/01/2022 9 30/01/2022 11 domestic campaign
> 1 30/01/2022 10/01/2022 20 31/01/2022 1 domestic campaign
> 1 31/01/2022 10/01/2022 21 01/02/2022 1 domestic campaign
> 1 01/02/2022 10/01/2022 22 19/05/2022 107 domestic campaign
> 1 19/05/2022 10/01/2022 129 20/05/2022 1
And I am looking to select only the first consecutive dates which would return the following:
Campaign Code Current Date Campaign Start Date Days Since Campaign Launch Next DaTe Next date - Current Date
domestic campaign 1 44571 44571 0 44572 1
domestic campaign 1 44572 44571 1 44573 1
domestic campaign 1 44573 44571 2 44574 1
domestic campaign 1 44574 44571 3 44575 1
domestic campaign 1 44575 44571 4 44576 1
domestic campaign 1 44576 44571 5 44577 1
domestic campaign 1 44577 44571 6 44578 1
domestic campaign 1 44578 44571 7 44579 1
domestic campaign 1 44579 44571 8 44580 1
Any help is much appreciated.

Answer 1

You can use ROW_NUMBER function subtracted from 'Next Date' to create groups for consecutive dates per campaign code, then use DENSE_RANK function to select only the first consecutive group for each campaign code.
With get_groups As
(
Select *,
Date_add('day', -ROW_NUMBER() Over (Partition By CampaignCode Order By NextDate), NextDate) As grp
From table_name
),
get_ranks As
(
Select *,
DENSE_RANK() OVER (Partition By CampaignCode Order By grp) As rnk
From get_groups
)
Select CampaignCode, CurrentDate, CampaignStartDate,
DaysSinceCampaign, NextDate, Nextdate_CurrentDate
From get_ranks
Where rnk = 1;
You may try to google "gaps and islands problem in SQL" for more details about this problem.
Side Note: ('Days Since Campaign', 'Campaign Start Date' and 'Next date - Current Date') can be easily calculated from other columns, so you don't need to store them in the table.