如何在SQL Server 2008 R2中对多列进行排序？

Question

There is a plain sort with order by clause with multiple columns separated by commas. But I am not looking for that. Please read below

The returned default result set is sorted by sequence column. Note sequence 46 and 47 which are in order with different ReqTag and Rank. I am trying to keep the ReqTag column together but sorted by sequence and Rank.

sequence | Reqtag | Rank
-------- | ------ | -------
42       | PD     | 1
43       | PD     | 2
46       | MQ     | 1
46       | SD     | 3
47       | MQ     | 2
47       | SD     | 4
48       | MO     | 1

Now, I want the display to be like below where sequence and rank column are used (desired result set)

sequence | Reqtag | Rank
-------- | ------ | ------
42       | PD     | 1
43       | PD     | 2
46       | MQ     | 1
47       | MQ     | 2
46       | SD     | 3
47       | SD     | 4
48       | MO     | 1

Any ideas are appreciated. Thank you for your time.

Answer 1

You can use window functions in the sort. I think you want:

order by min(sequence) over (partition by reqtag),
         min(rank) over (partition by reqtag),
         rank

Answer 2

If the order of the ReqTag is not important other than that they are grouped together then you should be able to change your sort to be the following:

SELECT sequence, ReqTag, Rank
FROM [Table]
ORDER BY ReqTag, sequence, Rank