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mike123
Master Smack Fu Yak Hacker
1462 Posts |
 Posted - 2007-04-27 : 05:57:30
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| Is this ever done? Can it be done? Basically I store a regular datetime(8) column, but my app only needs the smallDateTime(4) for this one particular query.Never seen or heard of this, maybe it would be slower.. It's just something that popped into my head, and wondering if anyone knows? :)Thanks!mike123 |
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SwePeso
Patron Saint of Lost Yaks
30421 Posts |
Posted - 2007-04-27 : 06:12:02
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| You can alter the column to a SMALLDATETIME if you have no need for seconds and milleseconds.One large difference is that SMALLDATETIME only handles dates up to June 2079, whereas DATETIME handle dates to December 9999.Peter LarssonHelsingborg, Sweden |
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mike123
Master Smack Fu Yak Hacker
1462 Posts |
Posted - 2007-04-27 : 06:17:03
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Hey Peso,I'm not quite yet ready to ALTER it, as a different query needs to use the full data. I have 2 seperate queries, with diff goals. I just thought it would be nice to trim it down for this 1 query and bring back only 4 bytes on the column since I am only using 4 bytes. No biggie tho.Thanks once again!!  |
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SwePeso
Patron Saint of Lost Yaks
30421 Posts |
Posted - 2007-04-27 : 06:20:44
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| Meanwhile you can create a calculated columnALTER TABLE Table ADD NewCol AS CAST(OldCol AS SMALLDATETIME)Peter LarssonHelsingborg, Sweden |
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mike123
Master Smack Fu Yak Hacker
1462 Posts |
Posted - 2007-04-27 : 06:33:23
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| Wow very interesting, so this column would also be stored on my tableAs I understand it, it will reduce bandwidth on selecting queries from my db server, however it will make my tables grow a little larger. tough decision for me to make, I'll do some performance testing!thx! |
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SwePeso
Patron Saint of Lost Yaks
30421 Posts |
Posted - 2007-04-27 : 06:40:18
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| No, it is not "stored" in the table. It is calculated per need basis.However, with SQL Server 2005, you can make the new column PERSISTED.Read all about it on Books Online.Peter LarssonHelsingborg, Sweden |
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selecting smallDateTime from datetime