Question

Sorry for the bad title – I simply do not know what to call the thing I want to do.

Here it goes:

In MS SQL Server 2008

I have a temp table with 4000+ rows created with the WITH statement looking like this:

ID (varchar) DATE (int)

AB1135000097 | 20151221
AB1135000097 | 20160119
AB1135000097 | 20160219
AB1135001989 | 20120223
AB1135001989 | 20120323
AB1135001989 | 20120423
.
.
.

I want to pair the data in date-ranges based on DATE.

AB1135000097 | 20151221 | 20160119
AB1135000097 | 20160119 | 20160219
AB1135001989 | 20120223 | 20120323
AB1135001989 | 20120323 | 20120423

Does this action have a name ? (I will add tags to the post when I know what I’m asking for)

Answer 1

I found a solution to my problem. Inspired by Jonathan Leffler’s solution. Thanks a lot!

It is based on adding row-numbers to the table ordered by ID and DATE, and then self-join with ROW+1 to get the next date as a second date column.

with 
SCHEDULE as
( -- remove duplicates and NULL entries

    select DISTINCT ID, DATE from TABLE1
    where DATE IS NOT NULL
),

SCHEDULE_WITH_ROW as
(
select * from (
    select DISTINCT ROW_NUMBER()
        OVER (ORDER BY ID, DATE) AS
        ROW, ID, DATE 
    from SCHEDULE) AS SCHED
)

select 
    S1.ID
    , S1.DATE
    , S2.DATE
from SCHEDULE_WITH_ROW S1
    join SCHEDULE_WITH_ROW S2 on S2.ID = S1.ID and S1.ROW + 1 = S2.ROW