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While retrieving data using select statement which way is faster either with * or with column names and why?
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If you are only selecting all columns from a table, using select * and select [columnnames].... will be the same. It is generally a better idea to select the column names explicitly. Should a table receive an extra column it would be loaded with a select * call, where the extra column is not needed. This can have several implications:
P.S. Please don't pressure for an answer (especially only one minute after asking). People answer as an when they can on this volunteer website. +1 - I would agree with all of these and add that explicitly naming the columns you need can give a benefit from the server using a cached plan if it recognises the query as having been run before. Using * does not guarantee the order that the columns are expanded so you can end up with different plans for effectively the same query.
Aug 31 '10 at 01:56 AM
Fatherjack ♦♦
@Fatherjack - did you +1 me on this, as i cannot see that being accounted to me anywhere? (hope voting is not broken)
Aug 31 '10 at 02:26 AM
WilliamD
G'ah!. Sorry. typed the words and then failed to follow up and hit the Thumbs-Up. Done now, voting is fine I am sure. ;)
Aug 31 '10 at 02:40 AM
Fatherjack ♦♦
Ok then. I wasn't sure, because there are still some bugs in OSQA and I recall a short discussion about votes going uncounted.
Aug 31 '10 at 02:49 AM
WilliamD
SSMS Tip to list all of the columns of a table without having to type them: Open up the Object Explorer payne and find the table, click + to see "Columns" and then drag the "Columns" to the Query pane. All of the column names will be listed for you, seperated by a comma. (This is easier done than said by the way.)
Sep 01 '10 at 07:54 AM
Mark
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Plz let me know the answer