yaml ​

Description ​

The yaml format represents a result as one YAML document containing a sequence of named mappings. Each mapping is one row, and its keys are column names.

The format supports input and output. Input keys select destination columns by name, and target declarations validate the values. Missing fields use the configured defaults. Unknown names raise an error unless ignore_unknown_fields = true.

YAML Core Schema scalars are supported, including strings, numbers, booleans, and null. Quote text that could otherwise be read as a number, boolean, or missing value. Anchors, aliases, and non-Core tags are rejected. Native array, tuple, map, and JSON targets validate nested sequences and mappings according to their declared types.

Example usage ​

Create a destination table:

CREATE TABLE people (id UInt32, name String);

Send this input as a separate request:

INSERT INTO people FORMAT yaml
- id: 1
  name: Ada
- id: 2
  name: Grace

Export the rows:

SELECT id, name FROM people ORDER BY id FORMAT yaml;

- "id": 1
  "name": "Ada"
- "id": 2
  "name": "Grace"

Format settings ​

There are no YAML-specific settings. Set the common ignore_unknown_fields option on an input statement when extra mapping keys should be skipped:

INSERT INTO people SETTINGS ignore_unknown_fields = true FORMAT yaml
<YAML document>