的SQL Server 2008：转换行到

Question

列我有两个表：现在

CREATE TABLE #A (id int, cond_id int) 
INSERT INTO #A (id, cond_id) 
VALUES (101,20), 
     (101,22), 
     (101,24), 
     (102,23), 
     (102,22) 

，每个ID可以有4个cond_ids最大。我想填充表#B，以便有一个id，并且根据cond_id升序将所有cond_ids填充到一行中作为一行。 类似于id 102，cond_id 22进入cond_id并且23进入cond_id2。

create table #B (id int, cond_id1 int, cond_id2 int, cond_id3 int, cond_id4 int) 

期望的结果：

表＃B

id cond_id1 cond_id2 cond_id3 cond_id4 
101 20  22  24  null 
102 22  23  null  null 

提前感谢！

Answer 1

因为你知道的最大列数，一个选择是使用row_number，max和case：

with cte as (
    select row_number() over (partition by id order by cond_id) rn, id, cond_id 
    from a) 
select id, 
    max(case when rn = 1 then cond_id end) cond_id1, 
    max(case when rn = 2 then cond_id end) cond_id2, 
    max(case when rn = 3 then cond_id end) cond_id3, 
    max(case when rn = 4 then cond_id end) cond_id4 
from cte 
group by id 

• SQL Fiddle Demo

---

或者你可以看看透视：

select id, [1] cond_id1, [2] cond_id2, [3] cond_id3, [4] cond_id4 
from 
    (select row_number() over (partition by id order by cond_id) rn, id, cond_id 
    from a) t 
pivot 
(
    max(cond_id) 
    for rn in ([1], [2], [3], [4]) 
) p 

• More Fiddle