private static String doubleToSql(final double value) {
        if (Double.isNaN(value) || Double.isInfinite(value)) {
            return "0";
        }
        return String.valueOf(value).replace(',', '.');
    }
Return the "where" part of the string appropriate for a SQL query.

@param dbTable the database table to use as prefix, or null if no prefix is required
@return the string without the "where" keyword
main/src/main/java/cgeo/geocaching/location/Viewport.java