Time - Adding minutes and seconds

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Time - Adding minutes and seconds

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neevmansoori

Posted Saturday, December 22, 2012 8:01 AM

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We sincerely thank you..
It Saves a lot of Efforts of mine. Smile

Post #1399678

Jeff Moden

Posted Saturday, December 22, 2012 10:40 AM

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neevmansoori (12/22/2012)

We sincerely thank you..
It Saves a lot of Efforts of mine. Smile

Yeah, but as old as this post is, I'm not sure that it answers what needs to be done for display purposes if the following data is present...

Connect Time2 totalTime2
23:00:00.0000000 01:00:00.0000000

--Jeff Moden

"RBAR is pronounced "ree-bar" and is a "Modenism" for "Row-By-Agonizing-Row".

First step towards the paradigm shift of writing Set Based code:
Stop thinking about what you want to do to a row... think, instead, of what you want to do to a column."

For better, quicker answers on T-SQL questions, click on the following...
http://www.sqlservercentral.com/articles/Best+Practices/61537/

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Post #1399692

dwain.c

Posted Sunday, December 23, 2012 5:47 PM

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Jeff Moden (12/22/2012)

neevmansoori (12/22/2012)

We sincerely thank you..
It Saves a lot of Efforts of mine. Smile

I think what Jeff is alluding to without saying it is the TIME data type is a "time of day" and not a "time duration." Adding them together implies that at least one of the values is a "time duration." How can you add 4PM + 6PM?

Perhaps though, it has some meaning in another multiverse.

No loops! No CURSORs! No RBAR! Hoo-uh!

INDEXing a poor-performing query is like putting sugar on cat food. Yeah, it probably tastes better but are you sure you want to eat it?

Need to UNPIVOT? Why not CROSS APPLY VALUES instead?
Since random numbers are too important to be left to chance, let's generate some!
Are you too recursively challenged?
Splitting strings based on patterns can be fast!

Post #1399777

Jeff Moden

Posted Sunday, December 23, 2012 10:39 PM

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What I'm actually trying to get people to realize is that using JUST the time for this type of stuff (EndTime = StartTime + Duration) is the wrong thing to do unless it's ok to "wrap the clock" after midnight. If you have a duration that exceeds 24 hours starting just before midnight of one day, then you really need to show that the call or whatever duration your trying to portray ended two days later just after midnight.

In other words, both StartTime and EndTime must show the date AND the time for both.

--Jeff Moden

Post #1399801

dwain.c

Posted Sunday, December 23, 2012 11:49 PM

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Jeff Moden (12/23/2012)

Of course. Sorry Jeff, I didn't mean to speak for you.

But of interest, what is the meaning in the physical world of the following addition?

2012-12-21 05:00 + 2012-12-24 07:00

If your answer is that you're adding the number of days between Jan 1, 1900 and Dec 12, 2012 (+ 7 hours) to the date Jan 21, 2012 (at 5AM), I'm with you. I'm just saying it's a kludge (albeit a widely used one). Because MS hasn't been so kind to provide a specific type for a date/time interval.

Personally, my preference is to use the DATETIME to hold the date and an INT (or BIGINT) to hold the minutes, or if need be seconds, to represent the interval. Ignoring for the moment the issues you might encounter using BIGINT.

Post #1399820

Jeff Moden

Posted Monday, December 24, 2012 6:33 AM

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No, no.... you were spot on. TIME columns are ok for durations of 1 day but aren't actually duration columns. I also have a hard time understanding why people would want to separate date and time even for display purposes unless they are, in fact, just trying to display duration. Certainly, I wouldn't store date and time separately.

I might store just the date if it's a column guaranteed to only ever need to be a whole date but then there's the problem of doing nasty little conversions like the one on this thread. For example, you asked if I was suggesting the following...

2012-12-21 05:00 + 2012-12-24 07:00

If the second date/time is supposed to be the duration and the first date/time is the start date, then kind of but not quite. If someone worked 1 hour, 13 minutes, and 59 seconds, then any of the following would work just fine to get the EndDate...

2012-12-21 05:00 + '01:13:59'
2012-12-21 05:00 + '1900-01-01 01:13:59' --Admittedly, confusing, but shows how things work.
StartDate + Duration -- Where both are data/time datatypes and the duration is stored as a result of (for example) '1900-01-01 01:13:59' .

Yeah... I know this stuff doesn't work for any of the "new" date/time datatypes. I think that MS really and unnecessarily made it a whole lot more difficult to do such simple things as adding a simple duration to a starting date and time. I wish they would have (no pun intended) spent the time making a proper "Duration" datatype that would allow you to store a (for example) 49 hour duration as something a little easier for folks to figure out other than 1900-01-03 01:00:00. For example, the following DOESN"T currently work...

SELECT Duration = CAST('49:00:00' AS DATETIME)

Instead, you have to go through a bunch of hooie to parse the hours, minutes, and seconds and then DATEADD each of those back to "0" (1900-01-01).

Same goes the other way around. Using subtraction between a start and end date/time is easy and accurate even across years. With the new date/time data types, you have to do something stupid like doing a DATEDIFF in milliseconds and then a DATEADD to "0" to reconvert it back to a date/time data type.

--Jeff Moden

Post #1399880

dwain.c

Posted Monday, December 24, 2012 5:35 PM

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+100% (agreement). Merry Christmas Jeff!

Post #1400005

Jeff Moden

Posted Tuesday, December 25, 2012 7:46 AM

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Merry Christmas Dwain.

--Jeff Moden

Post #1400051

dwain.c

Posted Tuesday, December 25, 2012 7:50 AM

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Jeff Moden (12/25/2012)

Merry Christmas Dwain.

Let me see. Christmas morning where you are and here you are posting on the SSC forum.

You must want that 32,000th post pretty bad!

Post #1400054

Jeff Moden

Posted Saturday, December 29, 2012 10:42 AM

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dwain.c (12/25/2012)

Jeff Moden (12/25/2012)

Merry Christmas Dwain.

Let me see. Christmas morning where you are and here you are posting on the SSC forum.

You must want that 32,000th post pretty bad!

Nah... number of posts is a nice badge but that's not why I post. SQL isn't only my job, it's a hobby. Some folks do Sudoku, cross word puzzles, video games, etc... I like figuring out SQL problems.

--Jeff Moden

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