T-SQL Multiple grouping

Question

I have follwing data :

Product Price   StartDate                   EndDate
Apples  4.9     2010-03-01 00:00:00.000     2010-03-01 00:00:00.000
Apples  4.9           


        

Answer 1

SELECT  product, price, MIN(start_date), MAX(end_date)
FROM    (
        SELECT  product, price, start_date, end_date,
                ROW_NUMBER() OVER (PARTITION BY product ORDER BY startDate) rn1,
                ROW_NUMBER() OVER (PARTITION BY product, price ORDER BY startDate) rn2
        FROM    mytable
        ) q
GROUP BY
        product, price, rn2 - rn1
ORDER BY
        product, MIN(start_date), price