> ## Documentation Index
> Fetch the complete documentation index at: https://axiom.co/docs/llms.txt
> Use this file to discover all available pages before exploring further.
# gettype
> This page explains how to use the gettype function in APL.
The `gettype` function returns the runtime type of its argument as a string. Use this function when you need to determine the data type of fields, validate data structures, or debug type-related issues in your queries.
## For users of other query languages
If you come from other query languages, this section explains how to adjust your existing queries to achieve the same results in APL.
In Splunk SPL, you use `typeof` to check types. APL's `gettype` provides similar functionality with consistent type names.
```sql Splunk example theme={null}
| eval field_type=typeof(field_name)
```
```kusto APL equivalent theme={null}
['sample-http-logs']
| extend field_type = gettype(field_name)
```
In ANSI SQL, type checking varies by database. APL's `gettype` provides a standardized approach to runtime type detection.
```sql SQL example theme={null}
SELECT TYPEOF(field_name) AS field_type FROM logs;
```
```kusto APL equivalent theme={null}
['sample-http-logs']
| extend field_type = gettype(field_name)
```
## Usage
### Syntax
```kusto theme={null}
gettype(expression)
```
### Parameters
| Name | Type | Required | Description |
| ---------- | ---- | -------- | ------------------------------------------------ |
| expression | any | Yes | The expression whose type you want to determine. |
### Returns
Returns a string representing the runtime type: `string`, `int`, `long`, `real`, `bool`, `datetime`, `timespan`, `dynamic`, `array`, `dictionary`, or `null`.
## Use case examples
Identify the data types of fields to ensure proper query operations and data validation.
**Query**
```kusto theme={null}
['sample-http-logs']
| extend status_type = gettype(status),
duration_type = gettype(req_duration_ms),
time_type = gettype(_time)
| project status, status_type, req_duration_ms, duration_type, _time, time_type
| limit 10
```
[Run in Playground](https://play.axiom.co/axiom-play-qf1k/query?initForm=%7B%22apl%22%3A%22%5B%27sample-http-logs%27%5D%20%7C%20extend%20status_type%20%3D%20gettype\(status\)%2C%20duration_type%20%3D%20gettype\(req_duration_ms\)%2C%20time_type%20%3D%20gettype\(_time\)%20%7C%20project%20status%2C%20status_type%2C%20req_duration_ms%2C%20duration_type%2C%20_time%2C%20time_type%20%7C%20limit%2010%22%7D)
**Output**
| status | status\_type | req\_duration\_ms | duration\_type | \_time | time\_type |
| ------ | ------------ | ----------------- | -------------- | -------------------- | ---------- |
| 200 | string | 145 | long | 2024-11-06T10:00:00Z | datetime |
| 404 | string | 89 | long | 2024-11-06T10:01:00Z | datetime |
| 500 | string | 234 | long | 2024-11-06T10:02:00Z | datetime |
This query identifies the data types of key fields in HTTP logs, helping ensure that data is in the expected format for analysis and troubleshooting type-related query issues.
Validate trace field types to ensure proper data ingestion and processing.
**Query**
```kusto theme={null}
['otel-demo-traces']
| extend service_type = gettype(['service.name']),
duration_type = gettype(duration),
kind_type = gettype(kind)
| summarize type_counts = count() by service_type, duration_type, kind_type
```
[Run in Playground](https://play.axiom.co/axiom-play-qf1k/query?initForm=%7B%22apl%22%3A%22%5B%27otel-demo-traces%27%5D%20%7C%20extend%20service_type%20%3D%20gettype\(%5B%27service.name%27%5D\)%2C%20duration_type%20%3D%20gettype\(duration\)%2C%20kind_type%20%3D%20gettype\(kind\)%20%7C%20summarize%20type_counts%20%3D%20count\(\)%20by%20service_type%2C%20duration_type%2C%20kind_type%22%7D)
**Output**
| service\_type | duration\_type | kind\_type | type\_counts |
| ------------- | -------------- | ---------- | ------------ |
| string | timespan | string | 8765 |
This query validates the types of trace fields, helping identify data quality issues where fields might have unexpected types due to ingestion problems.
Detect type inconsistencies in security logs that might indicate data manipulation or logging errors.
**Query**
```kusto theme={null}
['sample-http-logs']
| extend id_type = gettype(id),
status_type = gettype(status),
uri_type = gettype(uri)
| summarize failed_attempts = count() by id_type, status_type, uri_type
| sort by failed_attempts desc
```
[Run in Playground](https://play.axiom.co/axiom-play-qf1k/query?initForm=%7B%22apl%22%3A%22%5B'sample-http-logs'%5D%20%7C%20extend%20id_type%20%3D%20gettype\(id\)%2C%20status_type%20%3D%20gettype\(status\)%2C%20uri_type%20%3D%20gettype\(uri\)%20%7C%20summarize%20failed_attempts%20%3D%20count\(\)%20by%20id_type%2C%20status_type%2C%20uri_type%20%7C%20sort%20by%20failed_attempts%20desc%22%7D)
**Output**
| id\_type | status\_type | uri\_type | failed\_attempts |
| -------- | ------------ | --------- | ---------------- |
| string | string | string | 2341 |
This query validates field types in failed authentication logs, helping detect anomalies where expected string fields might have different types due to injection attempts or data corruption.
## List of related functions
* [isnull](/apl/scalar-functions/string-functions/isnull): Checks if a value is null. Use this to specifically test for null values rather than getting the type.
* [isnotnull](/apl/scalar-functions/string-functions/isnotnull): Checks if a value is not null. Use this in filters when you need to exclude null values.
* [parse\_json](/apl/scalar-functions/string-functions/parse-json): Parses JSON strings into dynamic types. Use this before gettype when working with JSON data.