Visual Query Builder

Question

George 2011-10-1

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/17210-visual-query-builder

采纳的回答： Oleg Komarov

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Hi i want to retrieve sql data using matlab.

The problem is that i want to use in the "where" statement a matlab variable.

Something like this:

e = exec(conn,'SELECT COLUMN1,COLUMN2 FROM DATABASE_NAME WHERE COLUMN1 IN (MATLAB_VARIABLE);

But there is an error: "Invalid Column Name".

I think that doesn't recognise that "MATLAB_VARIABLE" is a matlab variable.

If i try this: e = exec(conn,'SELECT COLUMN1,COLUMN2 FROM DATABASE_NAME WHERE COLUMN1 IN (MATLAB_VARIABLE(1)); again the following error occus:"MATLAB_VARIABLE" is not a recognised built in funtion name

Any help would be appreciated

Thanks George

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Answer 1

Oleg Komarov 2011-10-1

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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/17210-visual-query-builder#answer_23179

在 MATLAB Online 中打开

You have to convert the content of matlab variable to a char variable.

If MATLAB_VARIABLE is already a char then simply:

str = ['SELECT COLUMN1,COLUMN2 FROM DATABASE_NAME WHERE COLUMN1 IN (' MATLAB_VARIABLE(1) ')'];
exec(conn, str)

Otherways, if it is a scalar double you have to use sprintf or num2str or str2double.

In case you have an array of values you have to use sprintf and interveal with commas.

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George 2011-10-1

Thank you very much. I follow the instructions from the link: http://www.mathworks.com/support/solutions/en/data/1-174JK/index.html?product=DB&solution=1-174JK

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