SQL Clone
SQLServerCentral is supported by Redgate
 
Log in  ::  Register  ::  Not logged in
 
 
 


DateAdd Function


DateAdd Function

Author
Message
webrunner
webrunner
SSCoach
SSCoach (16K reputation)SSCoach (16K reputation)SSCoach (16K reputation)SSCoach (16K reputation)SSCoach (16K reputation)SSCoach (16K reputation)SSCoach (16K reputation)SSCoach (16K reputation)

Group: General Forum Members
Points: 16760 Visits: 4141
jpowers (3/4/2009)
I thought it was a dead giveaway that only one answer had the correct date prefix (2009-02-09). The wrong answers had 2009-02-10 and 2009-02-08. Except for clicking on the wrong button on mistake, I can't understand why anyone would miss this question.


I got the original question correct, not because of the date but simply by doing the calculations in my head (in this case that was relatively easy for me). I almost second-guessed myself because it seemed uncharacteristic that the obvious QOTD answer was the correct one. Usually there is some trick involved.

But I got the second question (the one posted in the comments) wrong, because of the way SQL Server rounds milliseconds. Go figure, as they say....

webrunner

-------------------
A SQL query walks into a bar and sees two tables. He walks up to them and says Can I join you?
Ref.: http://tkyte.blogspot.com/2009/02/sql-joke.html
john.arnott
john.arnott
SSCertifiable
SSCertifiable (7.1K reputation)SSCertifiable (7.1K reputation)SSCertifiable (7.1K reputation)SSCertifiable (7.1K reputation)SSCertifiable (7.1K reputation)SSCertifiable (7.1K reputation)SSCertifiable (7.1K reputation)SSCertifiable (7.1K reputation)

Group: General Forum Members
Points: 7072 Visits: 3059
Webrunner (and others following the subthread on my supplemental quiz question),

The rounding of milliseconds in DATETIME data is to .000, .003, or .007. Keep this in mind when designing queries that test for a time being within a range. An easy error to make would be to try to define a day with the BETWEEN operator. If we want to see if a time value is on the same day as some other time, you may be tempted to strip that target datetime down to just the date and then append a "highest possible" time value.

With this code, a Time_1 value of '2009-03-05 00:00:00.001' would return true, probably not what you'd want.

declare @time_1 datetime
declare @startTime datetime
declare @endTime datetime
set @time_1 = '2009-03-05 00:00:00.001'
set @startTime = '2009-03-04 00:00:00.00'
set @endTime = '2009-03-04 23:59:59.999'
Print '@startTime is ' + convert(char(23),@startTime,121)
Print '@time_1 is ' + convert(char(23),@time_1,121)
Print '@endTime is ' + convert(char(23),@endTime,121)
If @time_1 between @startTime and @endTime
print 'True'




Play with the values of @time_1 to understand the effect of rounding.

A better date-range test would be to test for greater than or equal to the start of a date and less than the start of the next date.

declare @time_1 datetime
set @time_1 = '2009-03-05 00:00:00.001'
If @time_1 >= '2009-03-04' and @time_1 < '2009-03-05' -- time portion defaults to zeroes
print 'True'
else
print 'False'



One final note: SQL 2008 introduces some new data types that allow separation of date and time and also greater precision on time.
Marcin Zawadzki
Marcin Zawadzki
Old Hand
Old Hand (354 reputation)Old Hand (354 reputation)Old Hand (354 reputation)Old Hand (354 reputation)Old Hand (354 reputation)Old Hand (354 reputation)Old Hand (354 reputation)Old Hand (354 reputation)

Group: General Forum Members
Points: 354 Visits: 79
That was too easy question.
Jerry Hung
Jerry Hung
SSCertifiable
SSCertifiable (7.6K reputation)SSCertifiable (7.6K reputation)SSCertifiable (7.6K reputation)SSCertifiable (7.6K reputation)SSCertifiable (7.6K reputation)SSCertifiable (7.6K reputation)SSCertifiable (7.6K reputation)SSCertifiable (7.6K reputation)

Group: General Forum Members
Points: 7618 Visits: 1208
I thought this was a trick question, but got it right anyway, whew~

SQLServerNewbie

MCITP: Database Administrator SQL Server 2005
girish.jawle
girish.jawle
Forum Newbie
Forum Newbie (1 reputation)Forum Newbie (1 reputation)Forum Newbie (1 reputation)Forum Newbie (1 reputation)Forum Newbie (1 reputation)Forum Newbie (1 reputation)Forum Newbie (1 reputation)Forum Newbie (1 reputation)

Group: General Forum Members
Points: 1 Visits: 4
answer c
kapil_kk
kapil_kk
SSChampion
SSChampion (10K reputation)SSChampion (10K reputation)SSChampion (10K reputation)SSChampion (10K reputation)SSChampion (10K reputation)SSChampion (10K reputation)SSChampion (10K reputation)SSChampion (10K reputation)

Group: General Forum Members
Points: 10617 Visits: 2778
easy one +1:-)

_______________________________________________________________
To get quick answer follow this link:
http://www.sqlservercentral.com/articles/Best+Practices/61537/
Go


Permissions

You can't post new topics.
You can't post topic replies.
You can't post new polls.
You can't post replies to polls.
You can't edit your own topics.
You can't delete your own topics.
You can't edit other topics.
You can't delete other topics.
You can't edit your own posts.
You can't edit other posts.
You can't delete your own posts.
You can't delete other posts.
You can't post events.
You can't edit your own events.
You can't edit other events.
You can't delete your own events.
You can't delete other events.
You can't send private messages.
You can't send emails.
You can read topics.
You can't vote in polls.
You can't upload attachments.
You can download attachments.
You can't post HTML code.
You can't edit HTML code.
You can't post IFCode.
You can't post JavaScript.
You can post emoticons.
You can't post or upload images.

Select a forum








































































































































































SQLServerCentral


Search