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