Time difference between two times in the same table

Question

Hello!

(Please note that I have seen a similar question on StackOverflow recently, however I can not find it anywhere - if anyone can find it please post the link)

I have a table that has a datetime field in it. For example:

Table data

DateTime date;
int number;

I need to find the difference between date in a row and date in the next row. I have tried with a query:

select date as current_date, date - (select top 1 date where date > current_date from data) as time_difference from date

however this won't work, because of "current_date". Is there a way I can do this with one query?

Answer 1

SELECT  date AS current_date, next_date - date AS difference
FROM    mytable mo
CROSS APPLY
        (
        SELECT  TOP 1 date AS next_date
        FROM    mytable mi
        WHERE   mi.date > mo.date
        ORDER BY
                date
        ) q