Forum Discussion
Convert Date/Time in UTC to Local Time with Daylight savings
- 7 years ago
Hi Anonymous ,
I think there are many ways, for example I tried to find a pattern in order to catch the November first Sunday or March second Sunday, and for your specific needs, maybe this custom function could work:
(datetimecolumn as datetime) => let date = DateTime.Date(datetimecolumn), time = DateTime.Time(datetimecolumn), firstSundayOfNovember = Date.StartOfWeek(#date(Date.Year(date), 11, 7), Day.Sunday), SecondSundayOfMarch = Date.StartOfWeek(#date(Date.Year(date), 3, 14), Day.Sunday), isSummerTime = (date = SecondSundayOfMarch and time >= #time(1,0,0)) or (date > SecondSundayOfMarch and date < firstSundayOfNovember) or (date = firstSundayOfNovember and time >= #time(1,0,0)), timeZone = (7 - Number.From(isSummerTime))*-1, MDT = DateTime.From(date) + #duration(0,Time.Hour(time),Time.Minute(time),Time.Second(time)) + #duration(0, timeZone, 0, 0) in MDT
So for dates from March Second Sunday at 1:00am until November First Sunday at 12:59:59am you will get your datetime - 6 hours and for dates from November First Sunday 1:00am until March Second Sunday at 12:59:59am you will get your datetime - 7 hoursAccording to Saint Google, the time is changed after 1:00am if you need it to be changed after 12:00am instead just remove first and last condition from isSummerTime
If you have any question or if you find any error on the code, just let me know.
Regards,
Gian Carlo Poggi
- 7 years ago
Sure Anonymous ,
Right click on Queries pane and add a new Blank Query:
Then right click on this new query and select Advanced Editor:
In this new window erase all, paste the my code and click DONE:
Now that query was converted into a function, you can rename it if you like, for example to "UTC_to_MDT":
Then in order to use this function in your table you have different options, one option is going to your query or table, then click on Add Column / Invoke Custom Function, then put a name to this new column, select your function (in my case UTC_to_MDT) and select the column from your table you need to apply this function to (in my case "Date"):
And then you will see the new date added :
Hope this helps.
Regards,
Gian Carlo Poggi
Hi Anonymous ,
I think there are many ways, for example I tried to find a pattern in order to catch the November first Sunday or March second Sunday, and for your specific needs, maybe this custom function could work:
(datetimecolumn as datetime) =>
let
date = DateTime.Date(datetimecolumn),
time = DateTime.Time(datetimecolumn),
firstSundayOfNovember = Date.StartOfWeek(#date(Date.Year(date), 11, 7), Day.Sunday),
SecondSundayOfMarch = Date.StartOfWeek(#date(Date.Year(date), 3, 14), Day.Sunday),
isSummerTime = (date = SecondSundayOfMarch and time >= #time(1,0,0))
or
(date > SecondSundayOfMarch and date < firstSundayOfNovember)
or
(date = firstSundayOfNovember and time >= #time(1,0,0)),
timeZone = (7 - Number.From(isSummerTime))*-1,
MDT =
DateTime.From(date)
+ #duration(0,Time.Hour(time),Time.Minute(time),Time.Second(time))
+ #duration(0, timeZone, 0, 0)
in
MDT
So for dates from March Second Sunday at 1:00am until November First Sunday at 12:59:59am you will get your datetime - 6 hours and for dates from November First Sunday 1:00am until March Second Sunday at 12:59:59am you will get your datetime - 7 hours
According to Saint Google, the time is changed after 1:00am if you need it to be changed after 12:00am instead just remove first and last condition from isSummerTime
If you have any question or if you find any error on the code, just let me know.
Regards,
Gian Carlo Poggi
This is a wonderful solution and works perfectly!
I have an add-on question to this. I have multiple time zones to deal with and have the Time Zone stored in the data table (e.g. Amercias/Vancouver). How would I go about updating this function to calculate the appropriate offset based on the time zone for each row?
Any guidance would be most appreciated.
Chris
- freshwave4 years ago
Helper I
Hi Chris,
I see no one replied to you, and if the data is on SQL Server 2016 or greater, it might be best to just let SQL Server do the time conversion to whatever TimeZone you are in, rather than building out for each one in Power BI. I am unsure whether other database types have the same ability or not.
You can see the info about the SQL Server conversion, and my revised Power BI code at https://community.powerbi.com/t5/Power-Query/Convert-Date-Time-in-UTC-to-Local-Time-with-Daylight-savings/m-p/1860915/highlight/true#M55319.
In my post at https://community.powerbi.com/t5/Power-Query/Convert-Date-Time-in-UTC-to-Local-Time-with-Daylight-savings/m-p/1854668/highlight/true#M55158, I mentioned a good video that explains the SQL Server ability to convert the timezone. If your database already knows what timezone it is in, you probably only need to do add the following to adjust it to EST, or change the value in quotes to whatever the TimeZone you want them all to change into.
AT TIME ZONE 'US Eastern Standard Time' AS EST
Hope this is helpful.
Jeff