68 lines
1.5 KiB
Markdown
68 lines
1.5 KiB
Markdown
|
## `LOG` [esql-log]
|
||
|
|
|
||
|
|
**Syntax**
|
||
|
|
|
||
|
|
:::{image} ../../../../../images/log.svg
|
||
|
|
:alt: Embedded
|
||
|
|
:class: text-center
|
||
|
|
:::
|
||
|
|
|
||
|
|
**Parameters**
|
||
|
|
|
||
|
|
`base`
|
||
|
|
: Base of logarithm. If `null`, the function returns `null`. If not provided, this function returns the natural logarithm (base e) of a value.
|
||
|
|
|
||
|
|
`number`
|
||
|
|
: Numeric expression. If `null`, the function returns `null`.
|
||
|
|
|
||
|
|
**Description**
|
||
|
|
|
||
|
|
Returns the logarithm of a value to a base. The input can be any numeric value, the return value is always a double. Logs of zero, negative numbers, and base of one return `null` as well as a warning.
|
||
|
|
|
||
|
|
**Supported types**
|
||
|
|
|
||
|
|
| base | number | result |
|
||
|
|
| --- | --- | --- |
|
||
|
|
| double | double | double |
|
||
|
|
| double | integer | double |
|
||
|
|
| double | long | double |
|
||
|
|
| double | unsigned_long | double |
|
||
|
|
| double | | double |
|
||
|
|
| integer | double | double |
|
||
|
|
| integer | integer | double |
|
||
|
|
| integer | long | double |
|
||
|
|
| integer | unsigned_long | double |
|
||
|
|
| integer | | double |
|
||
|
|
| long | double | double |
|
||
|
|
| long | integer | double |
|
||
|
|
| long | long | double |
|
||
|
|
| long | unsigned_long | double |
|
||
|
|
| long | | double |
|
||
|
|
| unsigned_long | double | double |
|
||
|
|
| unsigned_long | integer | double |
|
||
|
|
| unsigned_long | long | double |
|
||
|
|
| unsigned_long | unsigned_long | double |
|
||
|
|
| unsigned_long | | double |
|
||
|
|
|
||
|
|
**Examples**
|
||
|
|
|
||
|
|
```esql
|
||
|
|
ROW base = 2.0, value = 8.0
|
||
|
|
| EVAL s = LOG(base, value)
|
||
|
|
```
|
||
|
|
|
||
|
|
| base: double | value: double | s:double |
|
||
|
|
| --- | --- | --- |
|
||
|
|
| 2.0 | 8.0 | 3.0 |
|
||
|
|
|
||
|
|
```esql
|
||
|
|
row value = 100
|
||
|
|
| EVAL s = LOG(value);
|
||
|
|
```
|
||
|
|
|
||
|
|
| value: integer | s:double |
|
||
|
|
| --- | --- |
|
||
|
|
| 100 | 4.605170185988092 |
|
||
|
|
|
||
|
|
|