LOG10

描述

返回以10为底的x的自然对数。

别名

• DLOG10

语法

LOG10(<x>)

参数

参数	说明
<x>	真数 必须大于 0

返回值

返回一个浮点数。

• 当 x 为 NULL 时，返回 NULL
• 当 x 为 NaN、0 或负数时，返回 NULL

举例

select log10(1);

+--------------------------+
| log10(cast(1 as DOUBLE)) |
+--------------------------+
|                      0.0 |
+--------------------------+

select log10(10);

+---------------------------+
| log10(cast(10 as DOUBLE)) |
+---------------------------+
|                       1.0 |
+---------------------------+

select log10(16);

+---------------------------+
| log10(cast(16 as DOUBLE)) |
+---------------------------+
|        1.2041199826559248 |
+---------------------------+

select log10(NULL);

+-------------+
| log10(NULL) |
+-------------+
|        NULL |
+-------------+

select log10(cast('nan' as double));

+------------------------------+
| log10(cast('nan' as double)) |
+------------------------------+
|                         NULL |
+------------------------------+