Joining date with datetime and values per day - sql

Question

I am writing a query so that I can fill my facttable. I have a table which registers the weather average per day, registered at 23:59:00 of each day (date).
I have another table in which climate control data of different rooms are registered, per minute (datetime).
And I also have a time dimension available in another database.
I want to fill my facttable with all the available timeKeys combined with all the data from my climate control table and my weather table.
I'm sorry for my English, it isn't my mother tongue.
So, to find the matching timeKey for the date values I wrote this query:
SELECT t.timeKey AS WeathertimeKey,
weather.date AS date,
weather.temperature,
weather.rainAmountMM,
weather.windDirection,
weather.windSpeed
FROM StarSchema.dbo.timeDim t, weather
WHERE DATEPART(mm, t.DATE) = DATEPART(mm, weather.date)
AND DATEPART(dd, t.DATE) = DATEPART(dd, weather.date)
AND DATEPART(Hour, t.DATE) = '23'
AND DATEPART(MINUTE, t.DATE) = '59'
RESULT: Result
My time dimension has a timeKey for every minute in 2015: timeDimension
The facttable I am trying to fill: facttable
My solution for filling the facttable was creating a view with the corresponding timeKey per day and then joining that view in my main query.
SELECT
t.timeKey as timeKey,
rt1.roomId AS roomKey,
1 AS roomDataKey,
1 AS usageKey,
1 AS knmiKey,
rt1.temperature AS temperature,
rt1.locWindow AS locWindow,
rt1.locDoor AS locDoor,
rh1.turnedOn AS turnedOn,
rh1.temperature AS temperatureHeater,
s.storyTemp AS storyTemp,
s.storyHumidity AS storyHumidity,
vw.temperature AS temperatureOutside,
vw.rainAmountMM AS rainAmountMM,
vw.windSpeed AS windSpeed,
vw.windDirection AS windDirection,
vu.gasM3 AS gasM3,
vu.electricityKWH AS electricityKWH
FROM StarSchema.dbo.timeDim t
INNER JOIN roomTemperature1 rt1 ON rt1.date = t.DATE
INNER JOIN roomHeating1 rh1 ON rt1.date = rh1.date
INNER JOIN story s ON s.date = rt1.date
INNER JOIN vw_timeKeyWeatherDay vw ON t.timeKey = vw.WeathertimeKey
INNER JOIN vw_timeKeyUsageDay vu ON t.timeKey = vu.UsagetimeKey
The result is as follows: result2
So now it only uses the timeKey of 23:59 of everyday.
I want the complete days in there, but how do I do this?
Can someone help me out?
And my apologies for my use of the English language, again.
I did my best :-)

Answer 1

If I understand your question property, you want to match two date columns which have a different level of precision: one is per minute the other one is per day. What I suggest is a query which stores the yyyy.mm.dd only for both. Then when you join you get a matching record every time.
You can do that by adding the number of days that distance each of your dates from the date 0 in SQL server
DECLARE #DVal DATE
DECLARE #DTVal DATETIME
SET #DVal = '2018-01-18'
SET #DTVal = '2018-01-18 12:02:01.003'
SELECT #DVal
SELECT #DTVal
SELECT DATEDIFF(D,0,#DTVal)
SELECT DATEDIFF(D,0,#DVal)
SELECT DATEADD(D,(DATEDIFF(D,0,#DTVal) ),0)
SELECT DATEADD(D,(DATEDIFF(D,0,#DVal) ),0)
Comments about the code above:
First I declare the variables, one DATE and one DATETIME and I give them slightly different values which are less than a day.
Then I select them so that we can see they are different
2018-01-18
2018-01-18 12:02:01.003
Then I select the difference in days between each date and 0, and we have the same number of days
43116
43116
Then I add this difference to the date 0, and we end up with two datetime values which are identical
2018-01-18 00:00:00.000
2018-01-18 00:00:00.000
I hope I have answered your question. Please comment on my answer if I have not. At least this is a starting point. If your goal is to get the complete range of minutes per day you can create two calculated columns, one based on the current date and the other one based on the current date +1 day, and join against the time table with a BETWEEEN ON clause, etc.