---
warning: DO NOT CHANGE THIS MANUALLY, THIS IS GENERATED BY https://github/duckdb/community-extensions repository, check README there
title: lttb
excerpt: |
  DuckDB Community Extensions
  Largest-Triangle-Three-Buckets and related time-series downsampling aggregate functions.

extension:
  name: lttb
  description: Largest-Triangle-Three-Buckets and related time-series downsampling aggregate functions.
  version: 0.1.0
  language: C++
  build: cmake
  license: MIT
  maintainers:
    - reformovo

repo:
  github: reformovo/duckdb-lttb
  ref: 33e4c2682250082de97664a98b099a80e7932e6a

docs:
  hello_world: |
    SELECT lttb(x, y, 4)
    FROM (VALUES (1, 0), (2, 10), (3, -5), (4, 8), (5, 0)) AS t(x, y);
  extended_description: |
    The lttb extension provides aggregate functions for time-series downsampling directly in SQL.

    It includes exact Largest-Triangle-Three-Buckets sampling with `lttb`, a ClickHouse-compatible
    alias `largestTriangleThreeBuckets`, a sorted-input fast path with `lttb_sorted`, selected
    index output with `lttb_indices`, approximate MinMax preselection with `minmax_lttb` and
    `minmax_lttb_sorted`, and per-bucket summaries with `bucket_stats`.

    Inputs may use numeric, decimal, date, and timestamp types. The sampled output preserves
    the input `x` and `y` types as `STRUCT(x, y)[]`.

extension_star_count: 2
extension_star_count_pretty: 2
extension_download_count: 927
extension_download_count_pretty: 927
image: '/images/community_extensions/social_preview/preview_community_extension_lttb.png'
layout: community_extension_doc
---

### Installing and Loading
```sql
INSTALL {{ page.extension.name }} FROM community;
LOAD {{ page.extension.name }};
```

{% if page.docs.hello_world %}
### Example
```sql
{{ page.docs.hello_world }}```
{% endif %}

{% if page.docs.extended_description %}
### About {{ page.extension.name }}
{{ page.docs.extended_description }}
{% endif %}

### Added Functions

<div class="extension_functions_table"></div>

|        function_name        | function_type |                                    description                                    |                                       comment                                        |                                                     examples                                                     |
|-----------------------------|---------------|-----------------------------------------------------------------------------------|--------------------------------------------------------------------------------------|------------------------------------------------------------------------------------------------------------------|
| lttb                        | aggregate     | Downsample points to n representative points using Largest-Triangle-Three-Buckets | Sorts input by x before sampling.                                                    | [SELECT lttb(x, y, 4) FROM (VALUES (1, 0), (2, 10), (3, -5), (4, 8), (5, 0)) AS t(x, y);]                        |
| largestTriangleThreeBuckets | aggregate     | Alias for lttb with ClickHouse-compatible naming                                  | Sorts input by x before sampling.                                                    | [SELECT largestTriangleThreeBuckets(x, y, 4) FROM (VALUES (1, 0), (2, 10), (3, -5), (4, 8), (5, 0)) AS t(x, y);] |
| lttb_sorted                 | aggregate     | Downsample already-sorted points to n representative points                       | Caller must guarantee input is ordered by x.                                         | [SELECT lttb_sorted(x, y, 4) FROM (VALUES (1, 0), (2, 10), (3, -5), (4, 8), (5, 0)) AS t(x, y);]                 |
| lttb_indices                | aggregate     | Return selected sorted-position indices from LTTB sampling                        | Indices are returned as BIGINT[].                                                    | [SELECT lttb_indices(x, y, 4) FROM (VALUES (1, 0), (2, 10), (3, -5), (4, 8), (5, 0)) AS t(x, y);]                |
| minmax_lttb                 | aggregate     | Downsample using MinMax preselection followed by LTTB                             | Approximate method for large inputs. Pass NULL for the default minmax_ratio.         | [SELECT minmax_lttb(x, y, 4, NULL) FROM (VALUES (1, 0), (2, 10), (3, -5), (4, 8), (5, 0)) AS t(x, y);]           |
| minmax_lttb_sorted          | aggregate     | Downsample already-sorted points using MinMax preselection followed by LTTB       | Approximate method for large inputs. Caller must guarantee input is ordered by x.    | [SELECT minmax_lttb_sorted(x, y, 4, NULL) FROM (VALUES (1, 0), (2, 10), (3, -5), (4, 8), (5, 0)) AS t(x, y);]    |
| bucket_stats                | aggregate     | Return per-bucket statistical summaries over y with x range boundaries            | Returns STRUCT(bucket_start, bucket_end, count, min, max, mean, std, first, last)[]. | [SELECT bucket_stats(x, y, 3) FROM (VALUES (1, 0), (2, 10), (3, -5), (4, 8), (5, 0)) AS t(x, y);]                |

### Overloaded Functions

<div class="extension_functions_table"></div>

This extension does not add any function overloads.

### Added Types

<div class="extension_types_table"></div>

This extension does not add any types.

### Added Settings

<div class="extension_settings_table"></div>

This extension does not add any settings.