使用SQL NEWID（）多一個爲了

Question

我有以下表（namesTbl）：

id  name  priority 
----------------------------------- 
1  Steve  2 
2  John  3 
3  Carol  1 
4  Peter  2 
5  Mike  1 

運行）的存儲過程，其中namesTbl由NEWID（有序然後我拿到後，讓我們說，以下。

id  name  priority 
----------------------------------- 
4  Peter  2 
2  John  3 
5  Mike  1 
1  Steve  2 
3  Carol  1 

我的問題是，我如何訂購第一行只能始終優先1？其餘的行應該隨機選擇。在這種情況下，第一行必須是Mike或Carol，因爲兩者的優先級都是1 ... !!

謝謝

Answer 1

試試這個：

Select id, name, priority 
    From (SELECT id, name, priority, newPriority 
      FROM (select id, name, priority, -1 as newPriority, 
         row_number() over (order by priority) as rn 
        from namesTBL) tbl 
     WHERE rn = 1 
     UNION 
     SELECT id, name, priority, RAND(100) newPriority 
      FROM (select id, name, priority, 1 as newPriority, 
         row_number() over (order by priority) as rn 
        from namesTBL) tbl 
     WHERE rn > 1 
     ) tbl 
order by newPriority 

看到它在這裏工作：http://sqlfiddle.com/#!6/17cbb/3

編輯

還有一個更好的版本：

select id, name, priority 
    from (select id, name, priority, 
       ABS(CHECKSUM(NewId())) % 100 rnd, 
       row_number() over (order by priority) as rn 
      from namesTBL) tbl 
order by case when rn=1 then -1 else rnd end 

看到它在SQLFiddle上工作：http://sqlfiddle.com/#!6/8cc28/2