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arkiboys
Master Smack Fu Yak Hacker
1433 Posts |
 Posted - 2007-08-13 : 11:58:08
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| There is a table with a lot of fields.An update query is written such as the following lines:update table1set field1 = table2.field1,field2 = table2.field2,field3 = table2.field3,...wheresourcefile = 'filename.csv'and table1.field25 = table2.field25Questions:1)Is it best to have an inner join update instead? why?2)should I break down the update query into several smaller updates? why?3)Would any of the answers above speed up the update?Thanks |
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ashley.sql
Constraint Violating Yak Guru
299 Posts |
Posted - 2007-08-13 : 12:06:40
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| since you have the data why don't you try a few test cases urself.create another test table and try the options you mentioned and see how the results change. and how the time changes. using the inner join again depends on what sort of data you have.Ashley Rhodes |
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Jeff Moden
Aged Yak Warrior
652 Posts |
Posted - 2007-08-14 : 00:30:44
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| You're missing a FROM in the UPDATE. Recommend you visit Books Online to see what the correct syntax for joined updates actually is.--Jeff Moden |
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Jeff Moden
Aged Yak Warrior
652 Posts |
Posted - 2007-08-14 : 00:35:02
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| AND, no, you cannot reference a file this way. Better to import the file, anyway.--Jeff Moden |
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breaking update query