今天生产-SQL日期计算案例

我有一个关于日期计算的问题

我有一个datetime列，名为

CreatedLocalTime

date，格式如下：

2015-11-15 19:48:50.000

我需要检索一个名为

Prod\u Date

的新列，其中包含：

if “CreatedLocalTime” between 
    (CreatedLocalTime 7 AM) 
    & (CreatedLocalTime+1 7 AM)
 return CreatedLocalTime date with DD/MM/YYYY format

换句话说，今天的产量=昨天上午7点到今天上午7点的总和

---

有什么帮助吗

对于

第7天上午

到

第1天上午7点

，您可以尝试：

SELECT CAST(CreatedLocalTime as date) 
...
FROM ...
WHERE ...
    CreatedLocalTime >= DATEADD(hour, 7, CAST(CAST(CreatedLocalTime as date) as datetime)) 
AND 
    CreatedLocalTime  < DATEADD(hour, 31, CAST(CAST(CreatedLocalTime as date) as datetime)) 
...

选择强制转换（CreatedLocalTime作为日期）
...
从…起
哪里
CreatedLocalTime>=日期添加（小时，7，强制转换（强制转换（CreatedLocalTime为日期）为日期时间））
及
CreatedLocalTime

---

对于

前一天上午7点

到

第7天上午7点

，将7替换为-14，将31替换为7。

看起来您需要类似于

DECLARE @StartDateTime Datetime 
DECLARE @EndDateTime Datetime 
SET @EndDateTime  = DATEADD(hour, 7,convert(datetime,convert(date,getdate())) )
SET @StartDateTime  = DATEADD(day, -1, @EndDateTime  )

--Print out the variables for demonstration purposes
PRINT '@StartDateTime = '+CONVERT(nchar(19), @StartDateTime,120)
PRINT '@EndDateTime   = '+CONVERT(nchar(19), @EndDateTime,120)

SELECT SUM (Production) AS Prod_Date FROM YourSchema.YourTable WHERE CreatedLocalTime >= @StartDateTime AND CreatedLocalTime < @EndDateTime

第一个版本效率更高，因为查询在开始时只需执行一次日期运算，而第二个版本涉及对每个记录执行DATEDIFF和DATEADD。对于大量数据，这将变得更慢

镀金的解决方案是在表中添加一个计算列

ALTER TABLE YourSchema.YourTable ADD EffectiveDate AS CONVERT(date, DATEDIFF(day,DATEADD(hour, -7, CreatedLocalTime ))))

然后是该列上的索引

CREATE INDEX IX_YourTable_EffectiveDate  ON YourSchema.YourTable (EffectiveDate )

这样你就可以写作了

DECLARE @YesterDay date = DATEADD(day,-1, getdate())
SELECT SUM (Production) AS Prod_Date 
FROM YourSchema.YourTable 
WHERE EffectiveDate = @YesterDay

另一种方式

SELECT  CASE WHEN CreatedLocalTime BETWEEN DATEADD(HOUR, 7,
                                                            CAST(CAST (CreatedLocalTime AS DATE) AS DATETIME))
                                            AND     DATEADD(HOUR, 31,
                                                            CAST(CAST (CreatedLocalTime AS DATE) AS DATETIME))
             THEN REPLACE(CONVERT(NVARCHAR, CreatedLocalTime, 103), ' ', '/')
        END AS CreatedLocalTime

如果需要，您可以为此编写else部分

SELECT  CASE WHEN CreatedLocalTime BETWEEN DATEADD(HOUR, 7,
                                                            CAST(CAST (CreatedLocalTime AS DATE) AS DATETIME))
                                            AND     DATEADD(HOUR, 31,
                                                            CAST(CAST (CreatedLocalTime AS DATE) AS DATETIME))
             THEN REPLACE(CONVERT(NVARCHAR, CreatedLocalTime, 103), ' ', '/')
        END AS CreatedLocalTime