SQL get values for only a few hours in given time period? - sql

Question

My first question here..!
I'm not an expert in SQL, so bear over with me please! :)
I have a web page (not created by me) which gets report data from a MSSQL database, on the web page you enter start date and end date and data are fetched in this time interval from 00:00 on start date until 23:59 on end date.
I have managed to add more queries to the SQL, but now I would like to, for certain values only to return values which were logged in the time range 00:00:00 until 04:00:00 every day in the selected time interval.
Currently values are logged once an hour, but not always consistently. So far I have made a workaround in my web page which shows the first 4 values and skips the next 20, this loops for the selected interval. This method works 98% of the time, but occasionally there are more or fewer than 24 logged values per day which can cause the shown values will be skewed one way or another.
What I would like to do is change my SQL query so that it only returns values in the time range I want (between midnight and 04:00) for every day in the selected period. I hope someone can help me achieve this or give me some hints! :)
This is the existing SQL query running with the variables which I do want all values for. There are more variables than this but I edited them out, all the Ren*Time variables is the ones I want to make a 4-hour-every-day version of.
SET NOCOUNT ON;
IF OBJECT_ID('tempdb..#tmpValues') IS NOT NULL BEGIN DROP TABLE #tmpValues END;
CREATE TABLE #tmpValues(Id INT PRIMARY KEY IDENTITY(1,1),BatchId INT, TimePoint DATETIME, Ren1Time DECIMAL(10,2), Ren2Time DECIMAL(10,2), Ren3Time DECIMAL(10,2), RenTotTime DECIMAL(10,2));
INSERT INTO #tmpValues(BatchId)
SELECT BatchId
FROM Batch
WHERE Batch.LogTime BETWEEN <StartTime> AND <StopTime>;
CREATE UNIQUE INDEX I_BatcId ON #tmpValues(BatchId);
UPDATE #tmpValues SET
TimePoint = (SELECT LogTime FROM Batch WHERE Batch.BatchId = #tmpValues.BatchId),
Ren1Time = (SELECT SUM(_Float) FROM LogData WHERE LogData.BatchId = #tmpValues.BatchId AND LogData.TagId = 21),
Ren2Time = (SELECT SUM(_Float) FROM LogData WHERE LogData.BatchId = #tmpValues.BatchId AND LogData.TagId = 25),
Ren3Time = (SELECT SUM(_Float) FROM LogData WHERE LogData.BatchId = #tmpValues.BatchId AND LogData.TagId = 29),
RenTotTime = (SELECT SUM(_Float) FROM LogData WHERE LogData.BatchId = #tmpValues.BatchId AND (LogData.TagId = 25 OR LogData.TagId = 29 OR LogData.TagId = 33));
DECLARE
#TimePoint DATETIME,
#Ren1Time FLOAT,
#Ren2Time FLOAT,
#Ren3Time FLOAT,
#RenTotTime FLOAT;
INSERT INTO #tmpValues(TimePoint, Ren1Time, Ren2Time, Ren3Time, RenTotTime)
VALUES(#TimePoint, #Ren1Time, #Ren2Time,#Ren3Time, #RenTotTime);
SET NOCOUNT OFF;
SELECT * FROM #tmpValues;
IF OBJECT_ID('tempdb..#tmpValues') IS NOT NULL BEGIN DROP TABLE #tmpValues END;

Answer 1

Don't mess around with temp tables and processing every column separately. I also have no idea what you're trying to do with those variables. You declare them, never set them, then do an INSERT with them, which will just insert a row of NULL values.
Assuming that you're using SQL Server, the DATEPART function will let you get the hour of the day.
SELECT
B.BatchID,
B.LogTime AS TimePoint,
SUM(CASE WHEN B.TagId = 21 THEN _Float ELSE 0 END) AS Ren1Time,
SUM(CASE WHEN B.TagId = 25 THEN _Float ELSE 0 END) AS Ren2Time,
SUM(CASE WHEN B.TagId = 29 THEN _Float ELSE 0 END) AS Ren3Time,
SUM(CASE WHEN B.TagId IN (21, 25, 29) THEN _Float ELSE 0 END) AS RenTotTime
FROM
dbo.Batch B
INNER JOIN LogData LD ON LD.BatchId = B.BatchId
WHERE
B.LogTime BETWEEN <StartTime> AND <StopTime> AND
DATEPART(HOUR, B.LogTime) BETWEEN 0 AND 4
GROUP BY
B.BatchID,
B.TimePoint

Answer 2

Thank you very much for your swift reply!
I couldn't exactly get your suggestion to work, but I did solve my problem thanks to your suggestion!
Since the SQL query which should be limited to the 4 hours is used only from one webpage and there are no values in this web page which should be shown for all 24 hours, I thought I could copy the existing .SQL file to a new file and simply change the following:
WHERE Batch.LogTime BETWEEN <StartTime> AND <StopTime>;
To
WHERE Batch.LogTime BETWEEN <StartTime> AND <StopTime> AND DATEPART(HOUR, Batch.LogTime) BETWEEN 0 AND 3;
I changed the call to the .SQL file in the web page from the old to the new file and it works! Simple as that! Also changed 0 AND 4 to 0 AND 3 since I found 03:59:59 will be included, which is exactly what I want :)