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returns

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Available from dbt v1.11 or with the dbt "Latest" release track.
functions/<filename>.yml


functions:
  - name: <function name>
    returns:
      data_type: <string> # required, warehouse-specific
      description: <markdown_string> # optional

Definition​

The returns property defines the output of a user-defined function (UDF). This is a required property for all functions and specifies what data type the function will return when executed.

Properties​

data_type (required)​

The data_type field specifies the data type that the function returns. This is a required field and must match the data types supported by your specific data platform.

Warehouse-specific data types

The data_type values are warehouse-specific. Use the data type syntax that your warehouse requires:

  • Snowflake: STRING, NUMBER, BOOLEAN, TIMESTAMP_NTZ, VARIANT, etc.
  • BigQuery: STRING, INT64, BOOL, TIMESTAMP, ARRAY<STRING>, STRUCT, etc.
  • Redshift: VARCHAR, INTEGER, BOOLEAN, TIMESTAMP, SUPER, etc.
  • Postgres: TEXT, INTEGER, BOOLEAN, TIMESTAMP, JSONB, etc.

Refer to your warehouse documentation for the complete list of supported data types and their syntax.

description​

An optional markdown string describing what the function returns. This is helpful for documentation purposes.

Examples​

Simple scalar function​

functions/schema.yml

functions:
  - name: is_valid_email
    description: Validates if a string is a properly formatted email address
    arguments:
      - name: email_string
        data_type: STRING
        description: The email address to validate
    returns:
      data_type: BOOLEAN
      description: Returns true if the string is a valid email format, false otherwise

Function with complex return type​

functions/schema.yml

functions:
  - name: calculate_metrics
    description: Calculates revenue and profit metrics
    arguments:
      - name: revenue
        data_type: DECIMAL(18,2)
      - name: cost
        data_type: DECIMAL(18,2)
    returns:
      data_type: DECIMAL(18,2)
      description: The calculated profit margin as a percentage

BigQuery function with ARRAY return type​

functions/schema.yml

functions:
  - name: split_tags
    description: Splits a comma-separated string into an array of tags
    arguments:
      - name: tag_string
        data_type: STRING
    returns:
      data_type: ARRAY<STRING>
      description: An array of individual tag strings

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