---
title: "Add new columns to table schema"
method: POST
path: "/v1/table/{id}/add_columns"
tags: ["Table", "Data"]
---

# Add new columns to table schema

`POST /v1/table/{id}/add_columns`

Add new columns to table `id` using SQL expressions or default values.

## Path parameters

- `id` string, required

## Query parameters

- `delimiter` string

## Request body

- AlterTableAddColumnsRequest
  - `id` string[]
  - `new_columns` NewColumnTransform[], required — List of new columns to add
    - `name` string, required — Name of the new column
    - `expression` string, nullable — SQL expression to compute the column value (optional if virtual_column is specified)
    - `virtual_column` AddVirtualColumnEntry
      - `input_columns` string[], required — List of input column names for the virtual column
      - `data_type` object, required — Data type of the virtual column using JSON representation
      - `image` string, required — Docker image to use for the UDF
      - `udf` string, required — Base64 encoded pickled UDF
      - `udf_name` string, required — Name of the UDF
      - `udf_version` string, required — Version of the UDF

## Response `200`

Add columns operation result

- AlterTableAddColumnsResponse
  - `transaction_id` string — Optional transaction identifier
  - `version` integer, required — Version of the table after adding columns

## Other responses

- `400` — Indicates a bad request error. It could be caused by an unexpected request body format or other forms of request validation failure, such as invalid json. Usually serves application/json content, although in some cases simple text/plain content might be returned by the server's middleware.
- `401` — Unauthorized. The request lacks valid authentication credentials for the operation.
- `403` — Forbidden. Authenticated user does not have the necessary permissions.
- `404` — A server-side problem that means can not find the specified resource.
- `503` — The service is not ready to handle the request. The client should wait and retry. The service may additionally send a Retry-After header to indicate when to retry.
- `5XX` — A server-side problem that might not be addressable from the client side. Used for server 5xx errors without more specific documentation in individual routes.

## Changes

- **2025-12-11** `6ad4337e3849` — 4 info
  - added the new optional request property `new_columns/items/virtual_column`
  - the request property `new_columns/items/expression` became nullable
  - the request property `new_columns/items/expression` became optional
  - added the optional property `transaction_id` to the response with the `200` status
- **2025-08-02** `89fbd6272646` — 1 info
  - endpoint added
- **2025-07-21** `6790486d1fac` — 1 breaking
  - api path removed without deprecation

[Change history](https://skmtc.dev/lance-format/apis/lance-namespace-specification/changes/v1/table/:id/add_columns/post.md)

---

[API](https://skmtc.dev/lance-format/apis/lance-namespace-specification.md) · [All operations](https://skmtc.dev/lance-format/apis/lance-namespace-specification/llms.txt) · [OpenAPI document](https://skmtc-service-production.skmtc.workers.dev/v1/apis/lance-format/lance-namespace-specification/revisions/6ad4337e3849/schema)