@Description("square root")
    @ScalarFunction
    @SqlType(StandardTypes.DOUBLE)
    public static double sqrt(@SqlType(StandardTypes.DOUBLE) double num)
    {
        return Math.sqrt(num);
    }
@Test
    public void testSqrt()
    {
        for (double doubleValue : DOUBLE_VALUES) {
            assertFunction("sqrt(" + doubleValue + ")", DOUBLE, Math.sqrt(doubleValue));
            assertFunction("sqrt(REAL '" + doubleValue + "')", DOUBLE, Math.sqrt((float) doubleValue));
        }
        assertFunction("sqrt(NULL)", DOUBLE, null);
    }