66 lines
1.5 KiB
Markdown
66 lines
1.5 KiB
Markdown
|
% This is generated by ESQL's AbstractFunctionTestCase. Do no edit it. See ../README.md for how to regenerate it.
|
|||
|
|
|
|||
|
|
**Examples**
|
|||
|
|
|
|||
|
|
```esql
|
|||
|
|
FROM employees
|
|||
|
|
| STATS COUNT(height)
|
|||
|
|
```
|
|||
|
|
|
|||
|
|
| COUNT(height):long |
|
|||
|
|
| --- |
|
|||
|
|
| 100 |
|
|||
|
|
|
|||
|
|
To count the number of rows, use `COUNT()` or `COUNT(*)`
|
|||
|
|
|
|||
|
|
```esql
|
|||
|
|
FROM employees
|
|||
|
|
| STATS count = COUNT(*) BY languages
|
|||
|
|
| SORT languages DESC
|
|||
|
|
```
|
|||
|
|
|
|||
|
|
| count:long | languages:integer |
|
|||
|
|
| --- | --- |
|
|||
|
|
| 10 | null |
|
|||
|
|
| 21 | 5 |
|
|||
|
|
| 18 | 4 |
|
|||
|
|
| 17 | 3 |
|
|||
|
|
| 19 | 2 |
|
|||
|
|
| 15 | 1 |
|
|||
|
|
|
|||
|
|
The expression can use inline functions. This example splits a string into multiple values using the `SPLIT` function and counts the values
|
|||
|
|
|
|||
|
|
```esql
|
|||
|
|
ROW words="foo;bar;baz;qux;quux;foo"
|
|||
|
|
| STATS word_count = COUNT(SPLIT(words, ";"))
|
|||
|
|
```
|
|||
|
|
|
|||
|
|
| word_count:long |
|
|||
|
|
| --- |
|
|||
|
|
| 6 |
|
|||
|
|
|
|||
|
|
To count the number of times an expression returns `TRUE` use a [`WHERE`](/reference/query-languages/esql/esql-commands.md#esql-where) command to remove rows that shouldn’t be included
|
|||
|
|
|
|||
|
|
```esql
|
|||
|
|
ROW n=1
|
|||
|
|
| WHERE n < 0
|
|||
|
|
| STATS COUNT(n)
|
|||
|
|
```
|
|||
|
|
|
|||
|
|
| COUNT(n):long |
|
|||
|
|
| --- |
|
|||
|
|
| 0 |
|
|||
|
|
|
|||
|
|
To count the same stream of data based on two different expressions use the pattern `COUNT(<expression> OR NULL)`. This builds on the three-valued logic ({{wikipedia}}/Three-valued_logic[3VL]) of the language: `TRUE OR NULL` is `TRUE`, but `FALSE OR NULL` is `NULL`, plus the way COUNT handles `NULL`s: `COUNT(TRUE)` and `COUNT(FALSE)` are both 1, but `COUNT(NULL)` is 0.
|
|||
|
|
|
|||
|
|
```esql
|
|||
|
|
ROW n=1
|
|||
|
|
| STATS COUNT(n > 0 OR NULL), COUNT(n < 0 OR NULL)
|
|||
|
|
```
|
|||
|
|
|
|||
|
|
| COUNT(n > 0 OR NULL):long | COUNT(n < 0 OR NULL):long |
|
|||
|
|
| --- | --- |
|
|||
|
|
| 1 | 0 |
|
|||
|
|
|
|||
|
|
|