presto-main/src/main/java/io/prestosql/type/DoubleOperators.java/DoubleOperators/multiply
class DoubleOperators:    @ScalarOperator(MULTIPLY)
    @SqlType(StandardTypes.DOUBLE)
    public static double multiply(@SqlType(StandardTypes.DOUBLE) double left, @SqlType(StandardTypes.DOUBLE) double right)
    {
        return left * right;
    }