Sql 选择值等于给定值或小于给定值且最接近该值的行

很抱歉把标题弄混了。请告诉我，是否可以通过db请求进行。假设我们有下表

   ind_id      name                 value       date
----------- -------------------- ----------- ----------
1           a                    10          2010-01-01
1           a                    20          2010-01-02
1           a                    30          2010-01-03
2           b                    10          2010-01-01
2           b                    20          2010-01-02
2           b                    30          2010-01-03
2           b                    40          2010-01-04
3           c                    10          2010-01-01
3           c                    20          2010-01-02
3           c                    30          2010-01-03
3           c                    40          2010-01-04
3           c                    50          2010-01-05
4           d                    10          2010-01-05

我需要查询所有行以包含给定日期的每个ind_id一次，如果给定日期没有ind_id，则取最近的较低日期，如果没有任何较低日期，则返回ind_id+name/ind_id对等于null。 例如，日期为2010-01-04，我希望得到以下结果：

ind_id      name                 value       date
----------- -------------------- ----------- ----------
1           a                    30          2010-01-03
2           b                    40          2010-01-04
3           c                    40          2010-01-04
4           d                    NULL        NULL

---

如果可能的话，如果有人帮我建立查询，我将非常感激。我使用的是SQL server 2008。

您可以使用以下内容：

declare @date date = '2010-01-04'

;with ids as
(
  select distinct ind_id
  from myTable
)
,ranks as
(
  select *
    , ranking = row_number() over (partition by ind_id order by date desc)
  from myTable
  where date <= @date
)
select ids.ind_id
  , ranks.value
  , ranks.date
from ids
  left join ranks on ids.ind_id = ranks.ind_id and ranks.ranking = 1

---

与前一个一样，最好通过连接到一个固定的数据表（如果可用）来获取ind_id/name信息。

这不是确切的答案，但会给你一个概念，因为我只是快速地写下它，不需要任何测试

use
go 
if
(Select value from table where col=@col1) is not null
--you code to get the match value
else if 
(Select LOWER(Date) from table ) is not null
-- your query to get the nerst dtae record
else
--you query withh null value
end

更新尝试：

with cte as
(select m.*,
        max(date) over (partition by ind_id) max_date,
        max(case when date <= @date then date end) over 
           (partition by ind_id) max_acc_date
 from myTable m)
select ind_id,
       name,
       case when max_acc_date is null then null else value end value, 
       max_acc_date date
from cte c
where date = coalesce(max_acc_date, max_date)

---

SQLFIDLE

以下是一个查询，返回您要查找的结果：

SELECT
    t1.ind_id
,   CASE WHEN t1.date <= '2010-01-04' THEN t1.value ELSE null END
FROM test t1
WHERE t1.date=COALESCE(
    (SELECT MAX(DATE)
    FROM test t2
    WHERE t2.ind_id=t1.ind_id AND t2.date <= '2010-01-04')
,   t1.date)

其思想是在相关查询中选择一行，使其ID与当前行的ID匹配，并且该日期是目标日期“2010-01-04”之前的最高日期

如果该行不存在，则返回当前行的日期。此日期需要替换为空；这就是上面的案例陈述所做的

这是一张支票。

检查一下

将选项与运算符一起使用

试一试

DECLARE @date DATETIME;

SET @date = '2010-01-04';

WITH temp1 AS
(
SELECT t.ind_id
, t.name
, CASE WHEN t.date <= @date THEN t.value ELSE NULL END AS value
, CASE WHEN t.date <= @date THEN t.date ELSE NULL END AS date
FROM test1 AS t
),

temp AS
(
SELECT *, ROW_NUMBER() OVER (PARTITION BY ind_id ORDER BY t.date DESC) AS rn
FROM temp1 AS t
WHERE t.date <= @date OR t.date IS NULL
)

SELECT *
FROM temp AS t
WHERE rn = 1

---

名称/标识id对相等-这是否意味着对于给定的标识，名称将始终相同？如果是这样，它代表数据库模式中的非规范化，除非底层数据来自多个表-显示的数据是来自单个表还是来自多个表？@Mark Bannister是的，我知道，这个表是另一个请求的结果：好的，它来自单个表-谢谢。谢谢，伙计们！如果我能接受所有的答案：感谢你的深刻见解，是的，前面的答案是错误的。Timofei没有要求maxvalue。我给出了答案和相应的演示。

with CTE_test
as 
(
    select int_id,
       max(date) MaxDate
    from test 
    where date<='2010-01-04 00:00:00:000'
    group by int_id
)
select A.int_id, A.[Value], A.[Date]
from test A
    inner join CTE_test B
       on a.int_id=b.int_id 
          and a.date = b.Maxdate
union all
select int_id, null, null 
from test 
where int_id not in (select int_id from CTE_test)

DECLARE @date date = '20100104'
SELECT ind_id,
       CASE WHEN date <= @date THEN value END AS value,
       CASE WHEN date <= @date THEN date END AS date
FROM dbo.test57 t
WHERE EXISTS (
              SELECT 1
              FROM dbo.test57 t2
              WHERE t.ind_id = t2.ind_id AND t2.date <= @date
              HAVING ISNULL(MAX(t2.date), t.date) = t.date
              )

DECLARE @date DATETIME;

SET @date = '2010-01-04';

WITH temp1 AS
(
SELECT t.ind_id
, t.name
, CASE WHEN t.date <= @date THEN t.value ELSE NULL END AS value
, CASE WHEN t.date <= @date THEN t.date ELSE NULL END AS date
FROM test1 AS t
),

temp AS
(
SELECT *, ROW_NUMBER() OVER (PARTITION BY ind_id ORDER BY t.date DESC) AS rn
FROM temp1 AS t
WHERE t.date <= @date OR t.date IS NULL
)

SELECT *
FROM temp AS t
WHERE rn = 1