Question

我需要从查询中获取值等于参数的行或基于ID关闭的行。

ID          Value
----------- -----------
1           1
1           2
1           3
2           1
2           2
3           1

CREATE TABLE #Test (ID int, Value int)

INSERT INTO #Test VALUES (1,1)
INSERT INTO #Test VALUES (1,2)
INSERT INTO #Test VALUES (1,3)
INSERT INTO #Test VALUES (2,1)
INSERT INTO #Test VALUES (2,2)
INSERT INTO #Test VALUES (3,1)

因此，对于值= 3，它应该返回

ID          Value
----------- -----------
1           3
2           2
3           1

对于ID = 1，我们有值3，而对于另一个，我想要的是与我给定输入3最接近的值。

编辑：

因此，对于value = 2，它应该返回

ID          Value
----------- -----------
1           2
2           2
3           1

Answer 1

只需使用GROUP BY上的ID对数据集进行分组，然后使用MAX获取最高值，并使用{{1}中提供的值限制数据像这样的子句：

WHERE

Answer 2

这允许返回ID和Value以外的数据字段，这是使用group by时的限制。

 Declare @Param Int = 2

    ;With cteAssigned As
    (
    Select ID, Value, 
            Row_Number() Over (Partition By ID Order By Value Desc) SortOrder
        From #Test
        Where Value <= @Param
    )
    Select * From cteAssigned Where SortOrder = 1

没有CTE编辑声明@Param Int = 2

Select * 
    From
        (
        Select ID, Value, 
                Row_Number() Over (Partition By ID Order By Value Desc) SortOrder
            From #Test
            Where Value <= @Param
        ) A
    Where SortOrder = 1

Answer 3

    SELECT ID ,MAX(VALUE) VALUE FROM #TEST
    GROUP BY ID

DECLARE @ID INT = 3
SELECT ID ,MAX(VALUE) VALUE FROM #TEST
 WHERE ID <= @ID
GROUP BY ID

then this is also correct only

Answer 4

CREATE TABLE #Test (ID int, Value int)

INSERT INTO #Test VALUES (1,1)
INSERT INTO #Test VALUES (1,2)
INSERT INTO #Test VALUES (1,3)
INSERT INTO #Test VALUES (2,1)
INSERT INTO #Test VALUES (2,2)
INSERT INTO #Test VALUES (3,1) 

DECLARE @Value INT = 0

SELECT DISTINCT
       t.ID,
       ca_t.Value
FROM #Test t
CROSS APPLY
    ( SELECT TOP 1 t2.Value
      FROM #Test t2
      WHERE t2.ID = t.ID
      ORDER BY ABS(t2.Value - @Value)
    ) ca_t

所以只需将@Value更改为您正在寻找的价值。

SQL获取具有给定值或最接近值

4 个答案: