Table Functions Reference¶

Complete reference for YAML table functions.

read_yaml¶

Reads YAML files into a table.

Signature¶

read_yaml(path VARCHAR, [options...]) → TABLE

Parameters¶

Parameter	Type	Default	Description
`path`	VARCHAR or VARCHAR[]	Required	File path, glob pattern, or list of files
`auto_detect`	BOOLEAN	`true`	Enable automatic type detection
`columns`	STRUCT	-	Explicit column type specification
`records`	VARCHAR	-	Path to nested array of records (dot notation)
`multi_document`	BOOLEAN	`true`	Handle multiple YAML documents
`expand_root_sequence`	BOOLEAN	`true`	Expand top-level sequences into rows
`ignore_errors`	BOOLEAN	`false`	Continue on parsing errors
`maximum_object_size`	INTEGER	16777216	Maximum file size in bytes
`sample_size`	INTEGER	20480	Rows to sample for schema detection
`maximum_sample_files`	INTEGER	32	Files to sample for schema detection

Returns¶

TABLE with columns inferred from YAML structure or specified via columns parameter.

Examples¶

-- Basic usage
SELECT * FROM read_yaml('config.yaml');

-- With glob pattern
SELECT * FROM read_yaml('data/*.yaml');

-- With file list
SELECT * FROM read_yaml(['file1.yaml', 'file2.yaml']);

-- With parameters
SELECT * FROM read_yaml('data.yaml',
    auto_detect = true,
    ignore_errors = true,
    columns = {'id': 'INTEGER', 'name': 'VARCHAR'}
);

-- Extract nested records
SELECT * FROM read_yaml('config.yaml', records = 'data.users');

-- Deeply nested path
SELECT * FROM read_yaml('app.yaml', records = 'config.database.tables');

read_yaml_objects¶

Reads YAML files preserving document structure.

Signature¶

read_yaml_objects(path VARCHAR, [options...]) → TABLE

Parameters¶

Same as read_yaml, plus:

Parameter	Type	Default	Description
`filename`	BOOLEAN	`false`	Include source filename column

Returns¶

TABLE with one row per file/document, preserving nested structure.

Examples¶

-- Read with filename
SELECT * FROM read_yaml_objects('configs/*.yaml', filename = true);

-- Access nested data
SELECT
    filename,
    yaml_extract_string(data, '$.name') AS name
FROM read_yaml_objects('data/*.yaml', filename = true);

read_yaml_frontmatter¶

Extracts YAML frontmatter from text files.

Signature¶

read_yaml_frontmatter(path VARCHAR, [options...]) → TABLE

Parameters¶

Parameter	Type	Default	Description
`path`	VARCHAR or VARCHAR[]	Required	File path or glob pattern
`as_yaml_objects`	BOOLEAN	`false`	Return raw YAML column
`content`	BOOLEAN	`false`	Include file body
`filename`	BOOLEAN	`false`	Include source filename

Returns¶

TABLE with columns from frontmatter fields, plus optional content and filename columns.

Examples¶

-- Basic frontmatter extraction
SELECT * FROM read_yaml_frontmatter('posts/*.md');

-- With all options
SELECT * FROM read_yaml_frontmatter('docs/**/*.md',
    content = true,
    filename = true
);

-- Raw YAML mode
SELECT frontmatter FROM read_yaml_frontmatter('posts/*.md',
    as_yaml_objects = true
);

parse_yaml¶

Parses a YAML string into a table.

Signature¶

parse_yaml(yaml_string VARCHAR) → TABLE

Parameters¶

Parameter	Type	Description
`yaml_string`	VARCHAR	YAML content to parse

Returns¶

TABLE with columns inferred from YAML structure.

Examples¶

-- Parse single document
SELECT * FROM parse_yaml('name: John
age: 30');

-- Parse multi-document
SELECT * FROM parse_yaml('---
name: Alice
---
name: Bob');

-- Parse sequence
SELECT * FROM parse_yaml('- item: one
- item: two');

yaml_each¶

Returns key-value pairs from a YAML object.

Signature¶

yaml_each(yaml_value YAML) → TABLE(key VARCHAR, value YAML)

Parameters¶

Parameter	Type	Description
`yaml_value`	YAML	A YAML object

Returns¶

TABLE with columns:

key VARCHAR - Key name
value YAML - Associated value

Examples¶

-- Iterate object
SELECT * FROM yaml_each('{a: 1, b: 2, c: 3}'::YAML);
-- Returns: (a, 1), (b, 2), (c, 3)

-- With value processing
SELECT key, yaml_type(value) AS type
FROM yaml_each(config);

yaml_array_elements¶

Unnests YAML array elements into rows.

Signature¶

yaml_array_elements(yaml_value YAML) → TABLE(value YAML)

Parameters¶

Parameter	Type	Description
`yaml_value`	YAML	A YAML array

Returns¶

TABLE with column:

value YAML - Each array element

Examples¶

-- Unnest array
SELECT * FROM yaml_array_elements('[1, 2, 3]'::YAML);
-- Returns: 1, 2, 3

-- Process elements
SELECT yaml_extract_string(value, '$.name') AS name
FROM yaml_array_elements('[{name: A}, {name: B}]'::YAML);

COPY TO (YAML Format)¶

Exports data to YAML files.

Signature¶

COPY (query) TO 'path' (FORMAT yaml [, STYLE style] [, LAYOUT layout])

Parameters¶

Parameter	Values	Default	Description
`FORMAT`	`yaml`	Required	Output format
`STYLE`	`flow`, `block`	`flow`	YAML formatting style
`LAYOUT`	`document`, `sequence`	`document`	Row organization

Examples¶

-- Basic export
COPY (SELECT * FROM users) TO 'users.yaml' (FORMAT yaml);

-- Block style with sequence layout
COPY (SELECT * FROM data) TO 'output.yaml'
(FORMAT yaml, STYLE block, LAYOUT sequence);

Direct File Access¶

YAML files can be queried directly:

-- These are equivalent:
SELECT * FROM 'data.yaml';
SELECT * FROM read_yaml('data.yaml');

Supported extensions: .yaml, .yml