Rewrite docs on tabular operators (#123)

Author: tothmano

apl/guides/exploring-the-union-operator-in-apl.mdx

@@ -1,37 +1,142 @@
 ---
-title: 'count'
-description: 'Learn how to return the number of events from your input dataset.'
-tags:
-    ['axiom documentation', 'documentation', 'axiom', 'tabular operators', 'count']
+title: count
+description: 'This page explains how to use the count operator function in APL.'
 ---
 
-Returns the number of events from the input dataset.
+The `count` operator in Axiom Processing Language (APL) is a simple yet powerful aggregation function that returns the total number of records in a dataset. You can use it to calculate the number of rows in a table or the results of a query. The `count` operator is useful in scenarios such as log analysis, telemetry data processing, and security monitoring, where you need to know how many events, transactions, or data entries match certain criteria.
 
-## Syntax
+## For users of other query languages
 
-```kusto
+If you come from other query languages, this section explains how to adjust your existing queries to achieve the same results in APL.
+
+<AccordionGroup>
+<Accordion title="Splunk SPL users">
+
+In Splunk’s SPL, the `stats count` function is used to count the number of events in a dataset. In APL, the equivalent operation is simply `count`. You can use `count` in APL without the need for additional function wrapping.
+
+<CodeGroup>
+```splunk Splunk example
+index=web_logs
+| stats count
+```
+
+```kusto APL equivalent
+['sample-http-logs']
 | count
 ```
+</CodeGroup>
 
-[Run in Playground](https://play.axiom.co/axiom-play-qf1k/explorer?initForm={%22apl%22:%22[%27sample-http-logs%27]\n|%20count%22,%22queryOptions%22:{%22quickRange%22:%2230d%22}})
+</Accordion>
+<Accordion title="ANSI SQL users">
+
+In ANSI SQL, you typically use `COUNT(*)` or `COUNT(field)` to count the number of rows in a table. In APL, the `count` operator achieves the same functionality, but it doesn’t require a field name or `*`.
+
+<CodeGroup>
+```sql SQL example
+SELECT COUNT(*) FROM web_logs;
+```
+
+```kusto APL equivalent
+['sample-http-logs']
+| count
+```
+</CodeGroup>
 
-## Returns
+</Accordion>
+</AccordionGroup>
 
-This function returns a table with a single data and column. The value of the only cell is the number of events in the dataset.
+## Usage
 
-## Examples
+### Syntax
 
 ```kusto
-['http-logs']
-| where method == 'GET'
 | count
 ```
 
-[Run in Playground](https://play.axiom.co/axiom-play-qf1k/explorer?initForm={%22apl%22:%22[%27sample-http-logs%27]\n|%20where%20method%20==%20%27GET%27\n|%20count%22,%22queryOptions%22:{%22quickRange%22:%2230d%22}})
+### Parameters
+
+The `count` operator does not take any parameters. It simply returns the number of records in the dataset or query result.
+
+### Returns
+
+`count` returns an integer representing the total number of records in the dataset.
+
+## Use case examples
+
+<Tabs>
+<Tab title="Log analysis">
+
+In this example, you count the total number of HTTP requests in the `['sample-http-logs']` dataset.
+
+**Query**
 
 ```kusto
-['http-logs']
+['sample-http-logs']
 | count
 ```
 
-[Run in Playground](https://play.axiom.co/axiom-play-qf1k/explorer?initForm=%7B%22apl%22%3A%22%5B%27sample-http-logs%27%5D%5Cn%7C%20count%22%2C%22queryOptions%22%3A%7B%22quickRange%22%3A%2230d%22%7D%7D)
+[Run in Playground](https://play.axiom.co/axiom-play-qf1k/explorer?initForm=%7B%22apl%22%3A%22%5B'sample-http-logs'%5D%20%7C%20count%22%7D)
+
+**Output**
+
+| count |
+|-------|
+| 15000 |
+
+This query returns the total number of HTTP requests recorded in the logs.
+
+</Tab>
+<Tab title="OpenTelemetry traces">
+
+In this example, you count the number of traces in the `['otel-demo-traces']` dataset.
+
+**Query**
+
+```kusto
+['otel-demo-traces'] |
+count
+```
+
+[Run in Playground](https://play.axiom.co/axiom-play-qf1k/explorer?initForm=%7B%22apl%22%3A%22%5B'otel-demo-traces'%5D%20%7C%20count%22%7D)
+
+**Output**
+
+| count |
+|-------|
+| 5000 |
+
+This query returns the total number of OpenTelemetry traces in the dataset.
+
+</Tab>
+<Tab title="Security logs">
+
+In this example, you count the number of security events in the `['sample-http-logs']` dataset where the status code indicates an error (status codes 4xx or 5xx).
+
+**Query**
+
+```kusto
+['sample-http-logs'] |
+where status startswith '4' or status startswith '5' |
+count
+```
+
+[Run in Playground](https://play.axiom.co/axiom-play-qf1k/explorer?initForm=%7B%22apl%22%3A%22%5B'sample-http-logs'%5D%20%7C%20where%20status%20startswith%20'4'%20or%20status%20startswith%20'5'%20%7C%20count%22%7D)
+
+**Output**
+
+| count |
+|-------|
+| 1200 |
+
+This query returns the number of HTTP requests that resulted in an error (HTTP status code 4xx or 5xx).
+
+</Tab>
+</Tabs>
+
+## List of related operators
+
+- [**summarize**](/apl/tabular-operators/summarize-operator): The `summarize` operator is used to aggregate data based on one or more fields, allowing you to calculate sums, averages, and other statistics, including counts. Use `summarize` when you need to group data before counting.
+- [**extend**](/apl/tabular-operators/extend-operator): The `extend` operator adds calculated fields to a dataset. You can use `extend` alongside `count` if you want to add additional calculated data to your query results.
+- [**project**](/apl/tabular-operators/project-operator): The `project` operator selects specific fields from a dataset. While `count` returns the total number of records, `project` can limit or change which fields you see.
+- [**where**](/apl/tabular-operators/where-operator): The `where` operator filters rows based on a condition. Use `where` with `count` to only count records that meet certain criteria.
+- [**take**](/apl/tabular-operators/take-operator): The `take` operator returns a specified number of records. You can use `take` to limit results before applying `count` if you're interested in counting a sample of records.