database toolbox - sql query problems

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Tom Hissel
Tom Hissel 2011-4-26
Im browsing access databases using matlab database toolbox and sql queries.
Simple queries work fine but when I want to use 'where' statements in combination with time/date columns (timestamps) I get in trouble. 'Systeemtijd' is a table in the database containing time indication in the format: 2011-02-25 16:56:00.
no problem: Time = fetch(conn, 'SELECT ALL Systeemtijd FROM "SWS_Pand OS1 GRFMET 1" ');
problematic: Time = fetch(conn, 'SELECT ALL Systeemtijd FROM "SWS_Pand OS1 GRFMET 1" WHERE Systeemtijd > {ts'2011-02-25 16:56:00'} ');
This kind of query works fine in access and in excel but for some reason the syntax is not accepted by matlab. Likely the reason is that matlab ends the query at the second ' where the other programs do not.
What is a working code/syntax to do a query like this in matlab?
Thank you
there was a typo before. I changed it.
The error message is just this one: ??? Error: File: queryoefenen.m Line: 27 Column: 99 Unexpected MATLAB expression.
It appears because matlab closes the query at the use of an apostrophe.
  2 个评论
Oleg Komarov
Oleg Komarov 2011-4-26
POst the error message: http://www.mathworks.com/matlabcentral/answers/6200-tutorial-how-to-ask-a-question-on-answers
Tom Hissel
Tom Hissel 2011-4-26
done, didnt do that before because it doesn't give significant information.

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采纳的回答

Tom Hissel
Tom Hissel 2011-4-26
OK after hours of puzzling I found a syntax that does get accepted by matlab and sql :)
this one works: 'SELECT ALL Systeemtijd FROM "SWS_Pand OS1 GRFMET 10" WHERE Systeemtijd>#02/26/2011 13:36:00#'
Thanks for your responses though! cheers

更多回答（2 个）

Oleg Komarov
Oleg Komarov 2011-4-26
I doubt this syntax is accepted by SQL:
'SELECT ALL Systeemtijd FROM "SWS_Pand OS1 GRFMET 1" WHERE Systeemtijd > ts{'2011-02-25 16:56:00'} '
  1 个评论
Tom Hissel
Tom Hissel 2011-4-26
SELECT ALL Systeemtijd FROM "SWS_Pand OS1 GRFMET 1" WHERE (Systeemtijd >{ts '2011-02-25 16:56:00'})

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Clemens
Clemens 2011-4-26
seems the string's not valid.
did you try replacing the apostrophes with ''(2 apostrophes) or " ?
  1 个评论
Tom Hissel
Tom Hissel 2011-4-26
yes. using quotation marks I get the following error:
??? Error using ==> database.fetch at 37
[Microsoft][ODBC Microsoft Access Driver] Syntax error (missing operator) in query expression 'Systeemtijd > ts [2011-02-25 16:56:00]}'.
Error in ==> queryoefenen at 27
Tijd = fetch(conn, 'SELECT ALL Systeemtijd FROM "SWS_Pand OS1 GRFMET 1" WHERE Systeemtijd > {ts "2011-02-25 16:56:00"} ');
Again.. syntax is not accepted.

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