Question

我需要从SQL Server 2008 R2表中查询数据。

表格：

 id    value
 1      0.63
 1      0.96
 5      1.15 
 5      1.2

我需要一个id唯一的表，每个id的值与最大距离为1.示例：

 id    value
 1      0.63 // it far from 1 than 0.96
 5      1.2  // it is far from 1 than 1.15

我知道如何通过创建一个tabe来检查每个id ony的值。我需要用一个查询来完成它。

select distinct id value 
from table
group by id, max(abs(value -1))

谢谢！

Answer 1

一种方法使用row_number()：

select id, value
from (select t.*, row_number() over (partition by id order by abs(value - 1)) as seqnum
      from t
where seqnum = 1;

可以将此作为聚合进行，但计算有点违反直觉：

select id,
       (case when max(abs(value - 1)) = max(value - 1) then max(value)
             else min(value)
        end) as value
from table t
group by id;

极值是最大值或最小值。您可以通过查看＆＃34; sign＆＃34;来确定这一点。最大值。

Answer 2

使用Row_Number窗口功能执行此操作

select * from
(
select id, value, row_number()over(partition by id order by abs(value -1)) as rn
from table
) A
Where Rn = 1

Answer 3

本质上与其他海报相同的答案，唉他们订购错误：

DECLARE @tt TABLE(id INT,value DECIMAL(28,2));
INSERT INTO @tt(id,value)VALUES(1,0.63),(1,0.96),(1,-0.25),(5,1.15),(5,1.2),(5,1.77);

;WITH cte AS (
    SELECT
        *,
        seqnr=ROW_NUMBER() OVER (PARTITION BY id ORDER BY ABS(value-1) DESC)
    FROM
        @tt
)
SELECT
    id,
    value
FROM    
    cte
WHERE
    seqnr=1;

结果：

+----+-------+
| id | value |
+----+-------+
|  1 | -0.25 |
|  5 | 1.77  |
+----+-------+

在距离给定值最远的表中查找值

3 个答案: