EXP - MaxCompute - 阿里雲

計算number的指數函數。

命令格式

double|decimal exp(<number>)

參數說明

number：必填。DOUBLE或DECIMAL類型。輸入為STRING、BIGINT類型時，會隱式轉換為DOUBLE類型後參與運算。

傳回值說明

返回DOUBLE或DECIMAL類型。返回規則如下：

number為DOUBLE、DECIMAL類型時會返回相應的類型。
number為STRING、BIGINT類型時，返回DOUBLE類型。
number值為NULL時，返回NULL。

樣本資料

為便於理解各函數的使用方法，本文為您提供來源資料，基於來源資料提供函數相關樣本。建立表mf_math_fun_t，並添加資料，命令樣本如下。

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');

查詢表mf_math_fun_t中的資料，命令樣本如下：

select * from mf_math_fun_t;
--返回結果。
+------------+-------------+-------------+--------------+------------+-------------+
| 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         |
+------------+-------------+-------------+--------------+------------+-------------+

使用樣本：待用資料樣本

--返回4.810477252069109。
select exp(3.1415926/2);
--返回NULL。
select exp(null);

使用樣本：表資料樣本

基於樣本資料，計算指數值，命令樣本如下。

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

返回結果如下。

+-------------------------+-------------------------+-------------------------+-------------------------+
| bigint_new              | double_new              | decimal_new             | string_new              |
+-------------------------+-------------------------+-------------------------+-------------------------+
| 0.000045399929762484854 | 1.6904588483790914      | 1.6904588483790914      | 22026.465794806718      |
| NULL                    | 0.9048374180359595      | 0.9048374180359595      | 0.000045399929762484854 |
| 0.36787944117144233     | NULL                    | 760890487.9368925       | 10686474581524.463      |
| 54.598150033144236      | 2.4351296512898744      | NULL                    | 9.357622968840175e-14   |
| 1.9287498479639178e-22  | 0.36787944117144233     | 0.36787944117144233     | 5.184705528587072e21    |
| 403.4287934927351       | 4.4816890703380645      | 4.4816890703380645      | 1.9287498479639178e-22  |
| 3.975449735908647e-31   | 0.0005530843701478336   | 0.0005530843701478336   | NULL                    |
| 2.718281828459045       | 0.000037170318684126734 | 0.000037170318684126734 | 0.36787944117144233     |
| 8.194012623990515e-40   | 13.197138159658358      | 13.197138159658358      | 1.0                     |
| 22026.465794806718      | 0.0030275547453758153   | 0.0030275547453758153   | 8.194012623990515e-40   |
+-------------------------+-------------------------+-------------------------+-------------------------+

MaxCompute：EXP