MATLAB: How can i use variable instead of constant to get data from thesql database

MySQL

qry = sprintf('Select fname From mydb.myface WHERE id=1');

working but

id=1; qry = sprintf('Select fname From mydb.myface WHERE id=id'); not working please help me!!

Best Answer

Your syntax is wrong. Try the following:

id = 1; qry = sprintf('Select fname From mydb.myface WHERE id = %d', id);

Related Solutions

MATLAB: I have to count the number of occurrences of a record (x) in a Table “Stocks” from a database “MultiProductInventory”

Looks like your database command is not finding the driver. It's difficult to give specific advice on this. I would suggest looking at the following:

MATLAB: Using Sql in matlab to get data

Two things about what you've written, a matlab one, and a sql one,

Matlab:

DD = ['SELECT * ' 'FROM Countries WHERE IDNr =']

is the same thing as

DD = ['SELECT * ', 'FROM Countries WHERE IDNr =']

It is a concatenation indeed and I recommend that you always put the , separator so the reader don't have to wonder if you made a mistake. Of course the result of that is:

DD ='SELECT * FROM Countries WHERE IDNr ='

so it's not clear why you didn't write that to start with.

SQL:

WHERE x = y

only allows you to specify one value for y, no more. So your SQL syntax is not correct. To select among a list of values, you use

WHERE x IN (val1, val2, val3, ..)

One way you could compose your statement:

ID = [8 , 4, 3];
IDstring = strjoin(compose('%d', ID), ',');
SQL = sprintf('SELECT * FROM Countries WHERE IDNr IN (%s)', IDstring);

Best Answer

Related Solutions

MATLAB: I have to count the number of occurrences of a record (x) in a Table “Stocks” from a database “MultiProductInventory”

MATLAB: Using Sql in matlab to get data

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