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Samadhi69
Starting Member
20 Posts |
 Posted - 2009-06-25 : 12:59:05
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| With imperative languages you can avoid some steps by failing fast with an AND declaration. IE if you have two conditions and the second may give you some error, but can only occur if the first condition is false then you write the code something likeif (condition1 AND condition2) {stuff}Because if condition1 is false it stops there.I'm trying to use this on a query to apply flag values in a table. The logic is based on whether any of 7 fields is over a value. Unfortunately the field is varchar and there are text values on some. However, these rows can be ignored when they have any text entries. So imperatively a failfast AND of checking for text then checking the 7 or statements would work.With SQL (I'm guessing because it's set based) it will not do this.The rows do not have unique keys (don't blame me I didn't create the db) so I can't use a where in (select ...) or something similar.Does anyone have suggestions?If con is the opposite of pro, what's the opposite of progress? |
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visakh16
Very Important crosS Applying yaK Herder
52326 Posts |
Posted - 2009-06-25 : 13:36:20
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you can add a new condition to this expression like (ISNUMERIC(yourflagfield)=0 OR (ISNUMERIC(yourflagfield)=1 AND CHARINDEX('d',yourflagfield)>0 AND CHARINDEX('e',yourflagfield)>0)) OR (condition1 AND condition2))so that other conditions will be evaluated only for numeric values |
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Lamprey
Master Smack Fu Yak Hacker
4614 Posts |
Posted - 2009-06-25 : 14:28:48
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| I don't think you can guarantee the order in which SQL will evaluate the expressions. Can you? |
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SwePeso
Patron Saint of Lost Yaks
30421 Posts |
Posted - 2009-06-25 : 14:30:07
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I don't think so.SQL Server treats all WHERE in a cost-based manner.
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Samadhi69
Starting Member
20 Posts |
Posted - 2009-06-25 : 16:49:43
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| I think for the purposes of this I'm going to set all the text values to '-1'. Fortunately I don't need to save them for this report otherwise I think I'd have to use a case statement which would slaughter my performance.If con is the opposite of pro, what's the opposite of progress? |
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Fail fast with AND?