> For the complete documentation index, see [llms.txt](https://docs.mediarithmics.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.mediarithmics.io/audience-and-activation/build-your-audiences/segment-reference/segment-builders/expert-otql-builder.md).
# Expert OTQL Builder
Write OTQL directly to define a segment, for when the builders cannot express what you need.
## What it is
The Expert OTQL Builder leverages the query tool to create a segment from an OTQL query you write yourself. It asks the most of you and gives the most expressiveness in return.
It is also what the segment creation wizard calls **User Expert Query**. That entry is not a segment type of its own - it is another way of producing a [Query segment](/audience-and-activation/build-your-audiences/segment-reference/segment-types/query-segment.md).
Reach it from **Builders > Expert: OTQL**, or from **Data studio > Query Tool**.
OTQL the language is documented in the **Setup & Monitor** section, under *OTQL documentation*. This page covers using it to build a segment.
## Building a segment
{% stepper %}
{% step %}
### Write the query
Follow the pattern `SELECT {id} FROM UserPoint WHERE ...`.
Because you are creating a segment of users, the `FROM` clause always refers to `UserPoint`:
```sql
SELECT {id} FROM UserPoint WHERE creation_date >= "2019-12-12"
```
{% endstep %}
{% step %}
### Run it
Run the query to confirm it is valid and returns results.
{% endstep %}
{% step %}
### Save it as a segment
Click **Save As > User Query Segment**.
{% endstep %}
{% endstepper %}
## Counting before you save
To check the potential volume of the segment you are about to create, use the `@count{}` directive:
```sql
SELECT @count{} FROM UserPoint WHERE creation_date >= "2019-12-12"
```
{% hint style="danger" %}
Register the segment **without** `@count{}`. The saved query must select ids, not a number:
```sql
SELECT {id} FROM UserPoint WHERE creation_date >= "2019-12-12"
```
{% endhint %}
## Editing one afterwards
A segment created this way is edited as OTQL, in the dedicated zone of the segment page - not in a builder. See [Query segment](/audience-and-activation/build-your-audiences/segment-reference/segment-types/query-segment.md#editing-one).
## Related pages
---
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