COS命令格式、参数和返回值_云原生大数据计算服务 MaxCompute(MaxCompute)-阿里云帮助中心

计算number的余弦函数，输入为弧度值。

命令格式

double|decimal cos(<number>)

参数说明

number：必填。DOUBLE或DECIMAL类型。输入为STRING、BIGINT类型时，会隐式转换为DOUBLE类型后参与运算。

返回值说明

返回DOUBLE或DECIMAL类型。返回规则如下：

number为DOUBLE、DECIMAL类型时会返回相应的类型。
number为STRING、BIGINT类型时，返回DOUBLE类型。
number值为NULL时，返回NULL。

示例数据

为便于理解各函数的使用方法，本文为您提供源数据，基于源数据提供函数相关示例。创建表mf_math_fun_t，并添加数据，命令示例如下。

create table if not exists mf_math_fun_t(
     int_data     int,
     bigint_data  bigint,
     double_data  double,
     decimal_data decimal,
     float_data   float,
     string_data  string
    );
insert into mf_math_fun_t values
(null, -10, 0.525, 0.525BD, cast(0.525 as float), '10'),
(-20, null, -0.1, -0.1BD, cast(-0.1 as float), '-10'),
(0, -1, null, 20.45BD, cast(-1 as float), '30'),
(-40, 4, 0.89, null, cast(0.89 as float), '-30'),
(5, -50, -1, -1BD, null, '50'),
(-60, 6, 1.5, 1.5BD, cast(1.5 as float), '-50'),
(-1, -70, -7.5, -7.5BD, cast(-7.5 as float),null ),
(-80, 1, -10.2, -10.2BD, cast(-10.2 as float), '-1' ),
(9, -90, 2.58, 2.58BD, cast(2.58 as float), '0'),
(-100, 10, -5.8, -5.8BD, cast(-5.8 as float), '-90');

查询表mf_math_fun_t中的数据，命令示例如下：

select * from mf_math_fun_t;
--返回结果。
+------------+-------------+-------------+--------------+------------+-------------+
| int_data   | bigint_data | double_data | decimal_data | float_data | string_data |
+------------+-------------+-------------+--------------+------------+-------------+
| NULL       | -10         | 0.525       | 0.525        | 0.525      | 10          |
| -20        | NULL        | -0.1        | -0.1         | -0.1       | -10         |
| 0          | -1          | NULL        | 20.45        | -1.0       | 30          |
| -40        | 4           | 0.89        | NULL         | 0.89       | -30         |
| 5          | -50         | -1.0        | -1           | NULL       | 50          |
| -60        | 6           | 1.5         | 1.5          | 1.5        | -50         |
| -1         | -70         | -7.5        | -7.5         | -7.5       | NULL        |
| -80        | 1           | -10.2       | -10.2        | -10.2      | -1          |
| 9          | -90         | 2.58        | 2.58         | 2.58       | 0           |
| -100       | 10          | -5.8        | -5.8         | -5.8       | -90         |
| NULL       | -10         | 0.525       | 0.525        | 0.525      | 10          |
| -20        | NULL        | -0.1        | -0.1         | -0.1       | -10         |
| 0          | -1          | NULL        | 20.45        | -1.0       | 30          |
| -40        | 4           | 0.89        | NULL         | 0.89       | -30         |
| 5          | -50         | -1.0        | -1           | NULL       | 50          |
| -60        | 6           | 1.5         | 1.5          | 1.5        | -50         |
| -1         | -70         | -7.5        | -7.5         | -7.5       | NULL        |
| -80        | 1           | -10.2       | -10.2        | -10.2      | -1          |
| 9          | -90         | 2.58        | 2.58         | 2.58       | 0           |
| -100       | 10          | -5.8        | -5.8         | -5.8       | -90         |
+------------+-------------+-------------+--------------+------------+-------------+

使用示例：静态数据示例

--返回2.6794896585028633e-8。
select cos(3.1415926/2);
--返回-0.9999999999999986。
select cos(3.1415926);
--返回NULL。
select cos(null);

使用示例：表数据示例

基于示例数据，计算余弦值，命令示例如下。

select cos(bigint_data) as bigint_new, cos(double_data) as double_new, cos(decimal_data) as decimal_new, cos(string_data) as string_new from mf_math_fun_t;

返回结果如下。

+---------------------+--------------------+----------------------+---------------------+
| bigint_new          | double_new         | decimal_new          | string_new          |
+---------------------+--------------------+----------------------+---------------------+
| -0.8390715290764524 | 0.8653239416229412 | 0.8653239416229412   | -0.8390715290764524 |
| NULL                | 0.9950041652780258 | 0.9950041652780258   | -0.8390715290764524 |
| 0.5403023058681398  | NULL               | -0.02964340851507803 | 0.15425144988758405 |
| -0.6536436208636119 | 0.6294120265736969 | NULL                 | 0.15425144988758405 |
| 0.9649660284921133  | 0.5403023058681398 | 0.5403023058681398   | 0.9649660284921133  |
| 0.960170286650366   | 0.0707372016677029 | 0.0707372016677029   | 0.9649660284921133  |
| 0.6333192030862999  | 0.3466353178350258 | 0.3466353178350258   | NULL                |
| 0.5403023058681398  | -0.7142656520272003| -0.7142656520272003  | 0.5403023058681398  |
| -0.4480736161291701 | -0.8464080412157756| -0.8464080412157756  | 1.0                 |
| -0.8390715290764524 | 0.8855195169413189 | 0.8855195169413189   | -0.4480736161291701 |
+---------------------+--------------------+----------------------+---------------------+