Question

I’m a noob to android and im am trying to query a sqlite table. I have read several tutorials and know how to query a table to return an entire column of values, but i can’t seem to figure out how to query a just a single value from a column by string. Any help is greatly appreciated. here is my code:

My successful code to query and return values for entire column:

public String getValue() {
        // TODO Auto-generated method stub
        String[] columns = new String[]{ KEY_ROWID, KEY_NAME, KEY_QUANTITY, KEY_OUNCES, KEY_VALUE };
        Cursor c = ourDatabase.query(DATABASE_TABLE, columns, null, null, null, null, null);
        String result = "";

        int iRow = c.getColumnIndex(KEY_ROWID);
        int iName = c.getColumnIndex(KEY_NAME);
        int iQuantity = c.getColumnIndex(KEY_QUANTITY);
        int iOunces = c.getColumnIndex(KEY_OUNCES);
        int iValue = c.getColumnIndex(KEY_VALUE);

        for (c.moveToFirst(); !c.isAfterLast(); c.moveToNext()){
            result = result + /*c.getString(iRow) + " " +*/ c.getString(iValue) + "\n";
        }           

    return result;
}

My attempt to query column for single value by string:

public String getSingleValue(String aCoin) throws SQLException{
    // TODO Auto-generated method stub
    String[] columns = new String[]{ KEY_ROWID, KEY_NAME, KEY_QUANTITY, KEY_OUNCES, KEY_VALUE};     
    Cursor c = ourDatabase.query(DATABASE_TABLE, columns, KEY_NAME + "=" + aCoin, null, null, null, null);
    String result = "";

    int iRow = c.getColumnIndex(KEY_ROWID);
    int iName = c.getColumnIndex(KEY_NAME);
    int iQuantity = c.getColumnIndex(KEY_QUANTITY);
    int iOunces = c.getColumnIndex(KEY_OUNCES);
    int iValue = c.getColumnIndex(KEY_VALUE);

    if (c != null){
        c.moveToFirst();
        result= c.getString(1);
        return result;
    }
    return null;
}

Answer 1

Change this

   String[] columns = new String[]{ KEY_ROWID, KEY_NAME, KEY_QUANTITY, KEY_OUNCES, KEY_VALUE };

to

        String[] columns = new String[]{ KEY_NAME};
    Cursor c = ourDatabase.query(DATABASE_TABLE, columns, KEY_NAME + "=" + aCoin, null, null, null, null);
    String result = "";
   if (c != null){
        c.moveToFirst();
        result= c.getString(0);
        return result;
    }
    return null;

If you want to only get the name column.