I have the following query which calculates today's midnight value (UTC) as a datetime:
SELECT CONVERT(DATE,GETDATE())+(GETDATE()-GETUTCDATE())
Result: 2011-11-03 19:00:00.000 (for GMT-5 on Nov. 4, 2011)
Not only that, but on occasion, it returns values like these:
2011-11-03 19:00:00.003
2011-11-03 19:00:00.007
2011-11-03 19:00:00.010
..., which are wrong!
There must be a better way to do this.
I already answered this with a solution using DATEADD and DATEDIFF with GETDATE() and GETUTCDATE(), similar to the example given in the original question, but since then I've discovered the datetimeoffset data type added in SQL Server 2008. This stores a datetime along with a timezone offset.
How you use this type will depend on whether you want to change the data type of your existing data. If you don't want to change anything, the following statement will return a datetime type with the local time of midnight:
SELECT CONVERT(datetime, SWITCHOFFSET(CONVERT(datetimeoffset,
CONVERT(date, GETDATE())),
DATENAME(TzOffset, SYSDATETIMEOFFSET())))
You could also convert any UTC time into local time using:
SELECT CONVERT(datetime, SWITCHOFFSET(CONVERT(datetimeoffset,
#myutctime,
DATENAME(TzOffset, SYSDATETIMEOFFSET())))
The datetimeoffset type is only available using SQL2008 and above. If you need to do this with 2005 and below, you can use a solution similar to the one in the original question, but altered to account for the fact that GETDATE() - GETUTCDATE() is not an atomic operation and will likely involve milliseconds of difference between when the two are executed.
SELECT DATEADD(minute,
DATEDIFF(minute, GETUTCDATE(), GETDATE()),
CONVERT(datetime, CONVERT(date, GETDATE())))
This will take the number minutes between GETDATE() and GETUTCDATE() and add them onto the local midnight time. Unfortunately, you have to convert back from date to datetime as DATEADD won't work with minutes if you give it a date. I'd suggest wrapping this into a user-defined function to make it look less verbose, e.g.
CREATE FUNCTION dbo.MidnightASUTC(#dt as datetime)
RETURNS datetime
AS
BEGIN
RETURN DATEADD(minute,
DATEDIFF(minute, GETUTCDATE(), GETDATE()),
CONVERT(datetime, CONVERT(date, #dt)))
END
SELECT dbo.MidnightAsUTC(GETDATE())
For a specific scenario like the one you've described ("today's midnight value (UTC) as a datetime"), a programmatic approach makes sense, but if you ever need to extend it to a different question (what was midnight UTC for this summer?), you may want to use a calendar table (to account for things like daylight savings time, etc).
Related
Here's what I use to get a HH:MM string:
CONVERT(varchar(5), time_requested, 108)
I'm thinking there may be a more elegant way, even maybe more efficient (see similar question on How to remove the time portion of a datetime value (SQL Server)?).
Requirements:
the final result has to be easily convertible to a string (in order to be able to concatenate some field time_created with a field such as date_created).
the following 2 cases must be covered: HH:MM and HH:MM:SS.
Declare #D datetime = GetDate() -- Data Type could be Time as well
Select CONVERT(varchar(8), #D, 108) -- for HH:MM:SS 11:27:26
Select CONVERT(varchar(5), #D, 108) -- for HH:MM 11:27
Failed to mention, if 2012+ you could also use Format()
Declare #D DateTime = '2016-10-22 13:30:25'
Select Format(#D,'HH:mm') -- 13:30
Select Format(#D,'hh:mm:ss tt') -- 01:30:25 PM
Your method is fine. It produces a string representation of the value.
You can also convert to a time data type:
select cast(time_requested as time)
But note that this is "format-less" -- it contains hours, minutes, seconds, and fractions of seconds. So, your method is probably the better approach.
I have to query an SQL Server database and the table's values use Epoch time (an int. Here's an example - 1438005018). I am wondering how I can write a query so that I can say the following...
select
*
from
tablename
where
epochdate between 'yesterday at 12:00' and 'today at 12:00' --this is the part I'm not sure about.
Ideally, if it's easy, I'd like the query to use non-epoch logic as Epoch time confuses the crap out of me. Maybe there's a quick way of converting in SQL Server?
I posted a link above in the comments that may be a more practical solution if you're able to deploy functions in the database you're working with, but if you're only able to query, this is an option to try as well (this assumes SQL Server 2008 and above):
declare #todayepoch bigint, #yesterdayepoch bigint;
select #todayepoch =
cast((cast(dateadd(hour, 12,
cast(cast(sysutcdatetime() as date) as datetime)) as decimal(24,10))
- cast(cast('1970-01-01' as datetime) as decimal(24,10)))
*60.0*60.0*24.0 as int), -- + 18000, --Eastern time
#yesterdayepoch =
cast((cast(dateadd(hour, -12,
cast(cast(sysutcdatetime() as date) as datetime)) as decimal(24,10))
- cast(cast('1970-01-01' as datetime) as decimal(24,10)))
*60.0*60.0*24.0 as int) -- + 18000 --Eastern time
select #todayepoch, #yesterdayepoch
select
*
from
tablename
where
epochdate between #yesterdayepoch and #todayepoch
I used UTC above as a presumption of comparing based on UTC times, but you could also compare to your time zone, with the appropriate addition/subtraction of your time zone difference in seconds (e.g., add 18000 to each variable to get noon in Eastern Standard Time).
You can test your results by using http://www.epochconverter.com/ to compare your values in your variables.
You query would look like the following:
DECLARE #dt_from DATETIME;
DECLARE #dt_to DATETIME;
SELECT
#dt_from=DATEADD(HH,-12,CAST(FLOOR(CAST(GETUTCDATE() AS FLOAT)) AS DATETIME)), -- strip time of current UTC date/time, and subtract 12 hrs
#dt_to=DATEADD(HH,+12,CAST(FLOOR(CAST(GETUTCDATE() AS FLOAT)) AS DATETIME)); -- strip time of current UTC date/time, and add 12 hrs
SELECT
*
FROM
tablename
WHERE
epochdate BETWEEN DATEDIFF(s,'1970-01-01',#dt_from) AND DATEDIFF(s,'1970-01-01',#dt_to);
When I execute the following, when the server's TimeZone is +01:00:
Convert(datetime, '2015-02-10T23:00:00Z', 127)
The result is:
10.02.2015 23:00:00
That is the Date at UTC-0. My expected value would be 11.02.2015 00:00:00, that is the date converted to the server's TimeZone.
Convert function doesn't convert time to UTC. It just simply changes the format of the input string. Here is what you need to do.
Find difference in hours between server local time and UTC time:
DECLARE #hour INT
SELECT #hour = DATEDIFF(HOUR, GETUTCDATE(), GETDATE())
Add the difference to the date you're trying to convert:
SELECT CONVERT(DATETIME, DATEADD(hour, #hour, '2015-02-10T23:00:00Z'), 127)
If you know your timezone difference in hours and you know that it's unlikely to be changed, then use a shorter version:
SELECT CONVERT(DATETIME, DATEADD(hour, -1, '2015-02-10T23:00:00Z'), 127)
You shouldn't really depend on the time zone setting of a server. However, if you have a specific time zone in mind, you could use my SQL Server Time Zone Support project.
After installation:
SELECT Tzdb.UtcToLocal('2015-02-10T23:00:00Z', 'Europe/Paris')
Choose a time zone from the list here.
I am trying to do a query between 2 dates. I would like to do it without having to worry about the time. When a user enters the 2 dates they want to search on, there is no selection for time. This means that the dates that they enter default to 12:00 AM.
The dates in the table do have times though. I just would like to ignore the times all together so the search brings back any records form said date range.
Here is my SQL:
TheDate BETWEEN #EnteredBeginDate AND #EnteredEndDate
So when a user does a range search between 8/6/2009 AND 9/9/2009 I want to return the records:
8/6/2009 11:33:02 AM
8/6/2009 11:39:17 AM
9/9/2009 8:21:30 AM
What's happening now is I only get back:
8/6/2009 11:33:02 AM
8/6/2009 11:39:17 AM
Can someone please recommend the best way to do this in SQL? I know how to do it in C#.
Just use DATEADD for the enddate to set it to midnight on the NEXT day...
TheDate BETWEEN #EnteredBeginDate AND DATEADD(day, 1, #EnteredEndDate)
If you want to be really precise, you could subtract a second or millisecond from that to make it 11:59:59 on your specified date:
TheDate BETWEEN #EnteredBeginDate AND DATEADD(second, -1, (DATEADD(day, 1, #EnteredEndDate)))
If you're on SQL Server 2008 or 2008 R2, you could use the new DATE datatype:
TheDate BETWEEN CAST(#EnteredBeginDate AS DATE) AND CAST(#EnteredEndDate AS DATE)
That strips off the time portion and looks only at the date
If you are using SQL Server 2008, then do this:
TheDate BETWEEN cast(#EnteredBeginDate as date) AND cast(#EnteredEndDate as date)
TheDate BETWEEN #EnteredBeginDate AND dateadd(day, 1, #EnteredEndDate)
If just the date is passed into SQL Server, it will make the time 12:00 AM. So, the end date on the the between clause is 9/9/2009 12:00 AM. Just add a day or modify the date passed into the query to include the correct time.
I have a variable of DateTime type in SQL.
Just need to have Date part of it.
please Help?
SELECT DATEADD(dd, 0, DATEDIFF(dd, 0, GETDATE()))
The result is: “2009-07-14 00:00:00.000”
Edit: guess the next variant is more common:
SELECT DATEADD(dd, DATEDIFF(dd, 0, GETDATE()), 0)
because of the day pattern can be easily changed to week or month pattern. It is very useful when the GROUP BY clause should group by week of month (reports).
This has been asked and answered before on Stack Overflow. In fact, it's been asked over and over:
Most efficient way in MS SQL to get date from date+time?
Best way to check for current date in where clause of sql query.
SQL Drop Time in DateTime
MS SQL Date Only Without Time
How to return the date part only from a SQL Server datetime datatype
Found this using Google
SELECT CONVERT(DATETIME, FLOOR(CONVERT(FLOAT, GETDATE())))
If you just need a varchar representation of the date, you can use the convert function, e.g.
select convert(varchar, getDate(), 102) /* 2009.07.14 */
If you need a datetime (midnight on the given date), you can just convert it back.
select convert(datetime, convert(varchar, getDate(), 102), 102)
-- Sneaky CAST/DATEDIFF trick strips off the time to get just the day (midnight)!
CAST(DATEDIFF(d,0,DateField) AS DATETIME) AS DayField
SQL Server 2008 has a date datatype that stores just the date, if you are inthis version, perhaps this would be a better datat type for you to use. Be warned though, Date doesn't work exactly like datetime for data manipulation.
SELECT DATEADD(day, DATEDIFF(day, '19900101', CURRENT_TIMESTAMP), '19900101')
A very useful article:
"The purpose of this article is to explain how the datetime types work in SQL Server, including common pitfalls and general recommendations."The ultimate guide to the datetime datatypes
Note that converting to varchar and back (convert(datetime, convert(varchar, getDate(), 102), 102)) is much slower.
If you want the format 'MM/DD/YY', use "CONVERT(varchar, #datetimevalue, 1) to display just the date. If you need it in datetime format, use "CONVERT(datetime, CONVERT(varchar, #datetimevalue, 1))".
I created an entry in my SQL blog about how to retrieve and display all possible formats of the CONVERT(varchar, ..) function:
http://jessesql.blogspot.com/2009/04/converting-datetime-values-to-varchar.html
A tip:
If you find yourself doing this often, you can create a scalar User Defined Function containing the time-stripping logic of your choice.
Be warned: SQL Server 2000 has some painful bugs involving UDF's in ON clauses.
datepart(day, datetimevalue)