SQL cursor error

I have been using the notepad SQLhelper (notesDBadapter) as a model, some of it works, some doesn't. I can get a cursor for 'fetchallrecords() but it crashes if I try a call passing an argument and using the 'WHERE'. The argument is passed but the cursor fails. My code in activity;

    public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.listselectedfile);    

    //Button ID clicked in previous activity
    Bundle bundle = getIntent().开发者_开发技巧getExtras();
    int BtnId = bundle.getInt("ButtonID");
    Toast.makeText(this, "ButtonID selected in Main:= " + BtnId, Toast.LENGTH_LONG) .show(); 

    mDbHelper = new SectionsDbAdapter(this);
    mDbHelper.open();
    fillData();

}  
    private void fillData() {
        // Get all of the notes from the database and create the item list
        //Cursor c = mDbHelper.fetchAllRecords();       <=== works fine
        Cursor c = mDbHelper.fetchRecordsbySource("UK"); <=== fails in DBhelper
        startManagingCursor(c);

        String[] from = new String[] { SectionsDbAdapter.KEY_DESC };
        //String[] from = new String[] { SectionsDbAdapter.KEY_SOURCE }; <=== can fetch this column from table
        int[] to = new int[] { R.id.tv_full_width };  //the R.id.xxx= view in the .xml file

        // Now create an array adapter and set it to display using our row
        SimpleCursorAdapter records =
            new SimpleCursorAdapter(this, R.layout.section_row_full_width, c, from, to);  //the .xml file containing the R.id.xxxx
        setListAdapter(records);
    }

In the DBhelper; This call works and returns the full table;

    public Cursor fetchAllRecords() {

    return mDb.query(DATABASE_TABLE, new String[] {
    KEY_ROWID, KEY_DESC, KEY_DEPTH, KEY_TWEB, 
    KEY_BF1, KEY_TF1, KEY_BF2, KEY_TF2, 
    KEY_IMAJOR, KEY_IMINOR, 
    KEY_PLMAJOR, KEY_PLMINOR, 
    KEY_JTORSION, KEY_AREA,  
    KEY_WARPING, KEY_CYCHANNEL, 
    KEY_SHAPE, KEY_SOURCE, 
    KEY_UNITS},null, null, null, null, null);
}

This call fails on the cursor (the argument is passed successfully);

    public Cursor fetchRecordsbySource(String source) throws SQLException {
    Log.v("In fetchRecordsbySource", "source = " +source);      

    Cursor mCursor = mDb.query(true, DATABASE_TABLE, new String[] {
    KEY_ROWID, KEY_DESC}, KEY_SOURCE + " = " + source, null, null, null, null, null);
    if (mCursor != null) {
        mCursor.moveToFirst();
    }
    return mCursor;
}

There is nothing obvious to me in the Eclipse debug, but, as a newby, I probably have not got the necessary perspective.

Can anyone spot the error?

---

In the code you have, if source is a non-numeric value, it needs to surrounded by single quotes, like this:

KEY_ROWID, KEY_DESC}, KEY_SOURCE + " = '" + source + "'", null, null, null, null, null)

But you will be better off if you pass your filter arguments as ?; this avoids (among other things) SQL injection attacks

KEY_ROWID, KEY_DESC}, KEY_SOURCE + " = ?", new String[] { source }, null, null, null, null)