Today Production - SQL Date Calculation case when - sql

Question

I have an issue regarding date calculations.
I have a datetime column called CreatedLocalTime date with this format: 2015-11-15 19:48:50.000
I need to retrieve a new column called Prod_Date with:
if “CreatedLocalTime” between
(CreatedLocalTime 7 AM)
& (CreatedLocalTime+1 7 AM)
return CreatedLocalTime date with DD/MM/YYYY format
On other words, today production = sum of yesterday from 7 AM till today at 7 AM.
Any help using case?

Answer 1

For day 7AM to day+1 7AM, you can try:
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))
...
For previous day 7AM to day 7AM, replace 7 by -14 and 31 by 7.

Answer 2

Another way..
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
You can write the else part for this, if needed

Answer 3

It looks like you want somthing along the lines of
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
But you could also look at it as all the times which after you remove 7 hours from them are yesterday
SELECT SUM (Production) AS Prod_Date
FROM YourSchema.YourTable
WHERE DATEDIFF(day,DATEADD(hour, -7, CreatedLocalTime ))) = 1
The First version will be more efficient as the query will only have to do the date arithmetic once at the start while the second involved executing DATEDIFF and DATEADD for every record. This will be slower on large amounts of data.
The Gold plated solution would be to add a computed column to your table
ALTER TABLE YourSchema.YourTable ADD EffectiveDate AS CONVERT(date, DATEDIFF(day,DATEADD(hour, -7, CreatedLocalTime ))))
And then an index on that column
CREATE INDEX IX_YourTable_EffectiveDate ON YourSchema.YourTable (EffectiveDate )
So you can write
DECLARE #YesterDay date = DATEADD(day,-1, getdate())
SELECT SUM (Production) AS Prod_Date
FROM YourSchema.YourTable
WHERE EffectiveDate = #YesterDay