Need help in SQL Queries using GUI controls or variables

Question

Hello, all
I have a big problem (I have already had with Visual Basic a few mounths ago) with Java while writing my SQL Queries.
I would like to know how I must do to use variable data or GUI control data in my SQL Query to select only some records.
Here, my first Query that works without any problem (no WHERE clause !!!) :
Statement requeteBedes = connectBedes.createStatement();
ResultSet resultatSeries = requeteBedes.executeQuery("SELECT * FROM Series");
initComboBoxSeries(resultatSeries);the method "initComboBoxSeries" fills a JComboBox with all the names of the series in my database.
Here comes my problem.I would like to use the value of the selected "series" in the JComboBox to search in another table of the same Database. I made another statement but it returns a Null ResultSet :
ResultSet resultatSearchAlbumsFromSeries = requeteBedes.executeQuery("SELECT * FROM bandes_dess WHERE  ser_nom = '" + strComboBoxSeriesSelected + "' "); The variable strComboBoxSeriesSelected contains the value of the selected line in the combobox with all the series, filled after the first query that is here above and that works very well.
Could some one help me and tell me how I must use variables or GUI controls values in my SQL Queries or tell me if there is a place where I could find an explanation of that kind of problems (like more "advanced SQL Queries", as the ones currently used in all the Learning Java 2 books)
Thank you all for your help.
Christian.

Answer 1

executeQuery() will never return null. At least that's what the spec says. You are probably catching an exception (probably a syntax error caused by a single quote in strComboBoxSeriesSelected) and ignoring it. Or do you mean the ResultSet contains no rows?
Anyway, to use parameterized queries, take a look at PreparedStatements. Your code should look like this using PreparedStatement:Statement requeteBedes = connectBedes.prepareStatement("SELECT * FROM bandes_dess WHERE  ser_nom = ?");
requeteBedes.setString(1, strComboBoxSeriesSelected);
ResultSet resultatSeries = requeteBedes.executeQuery();Alin.