Question

如果我从dbo.targetsvssales表中选择全部，我会得到以下结果：

    Date   | Sales | Targets
_____________________________
2017-01-01     10      10
2017-02-01     19      20
2017-03-01     31      30
2017-04-01     38      40
2017-05-01     49      50
2017-06-01     62      60
2017-07-01     70      70
2017-08-01     75      80
2017-09-01     88      90
2017-10-01     101     100
2017-11-01     105     110
2017-12-01     105     120

我想只选择小于当前日期的销售数据，将未来日期的结果保留为空，但保持目标值不变。所以select语句的结果是：

    Date   | Sales | Targets
_____________________________
2017-01-01     10      10
2017-02-01     19      20
2017-03-01     31      30
2017-04-01     38      40
2017-05-01     49      50
2017-06-01     62      60
2017-07-01     70      70
2017-08-01     75      80
2017-09-01     88      90
2017-10-01     101     100
2017-11-01     105     110
2017-12-01     NULL    120

这需要能够全年工作，以及具有每周和每日精度的表作为日期列，所以使用

WHERE DATE > GETDATE()

或类似的东西是理想的。任何帮助或建议将不胜感激。

Answer 1

使用case定义此列的结果：

CASE WHEN DATE <= GETDATE()
     THEN Sales
 END AS Sales

注意我已经颠倒了你的逻辑并跳过了else null，因为如果省略，这仍然是默认的。

有关案例的更多信息：http://modern-sql.com/feature/case

Answer 2

案例将适用于此问题。

CASE WHEN DATE<=GETDATE() THEN Sales ELSE NULL END

Answer 3

使用此：

select Date, case when Date > getdate() then NULL else Sales end as Sales, Targets 
from dbo.targetsvssales

SQL HERE

Answer 4

您可以使用Cas When语句

select date,
 CASE 
  WHEN Date <= GETDATE()
  THEN Sales
  else NULL
 End as Sales,
 targets
from dbo.targetsvssales

Answer 5

使用ROW_NUMBER和CASE：

CREATE TABLE T (
    MDate DATE,
    Sales INT,
    Targetes INT
    );

INSERT INTO T VALUES
('2017-01-01',     10 ,     10),
('2017-02-01',     19 ,     20),
('2017-03-01',     31 ,     30),
('2017-04-01',     38 ,     40),
('2017-05-01',     49 ,     50),
('2017-06-01',     62 ,     60),
('2017-07-01',     70 ,     70),
('2017-08-01',     75 ,     80),
('2017-09-01',     88 ,     90),
('2017-10-01',     101,     100),
('2017-11-01',     105,     110),
('2017-12-01',     105,     120);

WITH CTE AS (
SELECT *, ROW_NUMBER () OVER (PARTITION BY Sales ORDER BY MDate) RN
FROM T
    )
    SELECT MDate, CASE WHEN RN = 1 THEN Sales ELSE NULL END AS Sales, Targetes
    FROM CTE;

如果您真的想与GETDATE()进行比较，那么我建议您使用IIF或CASE作为：

SELECT MDate, IIF(IIF(MDate <= GetDate(), Sales, NULL) AS Sales, Targetes
FROM T;

<强> Demo

Answer 6

DECLARE @targetsvssales AS TABLE ([Date] DATE,   Sales MONEY, Targets MONEY)
INSERT INTO @targetsvssales VALUES
('2017-01-01',10,10),
('2017-02-01',19,20),
('2017-03-01',31,30),
('2017-04-01',38,40),
('2017-05-01',49,50),
('2017-06-01',62,60),
('2017-07-01',70,70),
('2017-08-01',75,80),
('2017-09-01',88,90),
('2017-10-01',101,100),
('2017-11-01',105,110),
('2017-12-01',105,120)

SELECT
 [Date] 
,CASE WHEN [DATE] > GETDATE() THEN NULL ELSE Sales END AS Sales 
,Targets

FROM @targetsvssales

如何有选择地从一列而不是另一列中清空值？

6 个答案: