---
metadata:
  - name: generator
    content: Diplodoc Platform v5.52.0
alternate:
  - https://ydb.tech/docs/en/yql/reference/syntax/select/from_as_table.md?version=v26.1
  - https://ydb.tech/docs/ru/yql/reference/syntax/select/from_as_table.md?version=v26.1
  - href: en/yql/reference/syntax/select/from_as_table.md
    type: text/markdown
    title: Markdown version
  - href: ../../../../llms.txt
    type: text/markdown
    title: llms.txt
sourcePath: en/core/yql/reference/syntax/select/from_as_table.md
---
> **Documentation Index:** Fetch the complete configuration index at https://ydb.tech/docs/en/llms.txt

# FROM AS_TABLE

Accessing named expressions as tables using the `AS_TABLE` function.

`AS_TABLE($variable)` lets you use the value of `$variable` as the data source for the query. In this case, the variable `$variable` must have the type `List<Struct<...>>`.

## Example


```yql
$data = AsList(
    AsStruct(1u AS Key, "v1" AS Value),
    AsStruct(2u AS Key, "v2" AS Value),
    AsStruct(3u AS Key, "v3" AS Value));

SELECT Key, Value FROM AS_TABLE($data);
```


You should either explicitly specify the modifiable columns in both the source and the target when using expressions with modifying queries such as [UPSERT INTO](https://ydb.tech/docs/en/yql/reference/syntax/upsert_into.md?version=v26.1) or [INSERT INTO](https://ydb.tech/docs/en/yql/reference/syntax/insert_into.md?version=v26.1):


```yql
$data = AsList(
    AsStruct(1u AS Key, "v1" AS Value),
    AsStruct(2u AS Key, "v2" AS Value),
    AsStruct(3u AS Key, "v3" AS Value));

INSERT INTO `my_table` (Key, Value) SELECT Key, Value FROM AS_TABLE($data);
```


Or you should omit them completely:


```yql
$data = AsList(
    AsStruct(1u AS Key, "v1" AS Value),
    AsStruct(2u AS Key, "v2" AS Value),
    AsStruct(3u AS Key, "v3" AS Value));

INSERT INTO `my_table` SELECT * FROM AS_TABLE($data);
```