druid/docs/querying/limitspec.md
Gian Merlino d007477742
Docusaurus build framework + ingestion doc refresh. (#8311)
* Docusaurus build framework + ingestion doc refresh.

* stick to npm instead of yarn

* fix typos

* restore some _bin

* Adjustments.

* detect and fix redirect anchors

* update anchor lint

* Web-console: remove specific column filters (#8343)

* add clear filter

* update tool kit

* remove usless check

* auto run

* add %

* Fix resource leak (#8337)

* Fix resource leak

* Patch comments

* Enable Spotbugs NP_NONNULL_RETURN_VIOLATION (#8234)

* Fixes from PR review.

* Fix more anchors.

* Preamble nix.

* Fix more anchors, headers

* clean up placeholder page

* add to website lint to travis config

* better broken link checking

* travis fix

* Fixed more broken links

* better redirects

* unfancy catch

* fix LGTM error

* link fixes

* fix md issues

* Addl fixes
2019-08-20 21:48:59 -07:00

55 lines
2.0 KiB
Markdown

---
id: limitspec
title: "Sort groupBy query results"
---
<!--
~ Licensed to the Apache Software Foundation (ASF) under one
~ or more contributor license agreements. See the NOTICE file
~ distributed with this work for additional information
~ regarding copyright ownership. The ASF licenses this file
~ to you under the Apache License, Version 2.0 (the
~ "License"); you may not use this file except in compliance
~ with the License. You may obtain a copy of the License at
~
~ http://www.apache.org/licenses/LICENSE-2.0
~
~ Unless required by applicable law or agreed to in writing,
~ software distributed under the License is distributed on an
~ "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
~ KIND, either express or implied. See the License for the
~ specific language governing permissions and limitations
~ under the License.
-->
The limitSpec field provides the functionality to sort and limit the set of results from a groupBy query. If you group by a single dimension and are ordering by a single metric, we highly recommend using [TopN Queries](../querying/topnquery.md) instead. The performance will be substantially better. Available options are:
### DefaultLimitSpec
The default limit spec takes a limit and the list of columns to do an orderBy operation over. The grammar is:
```json
{
"type" : "default",
"limit" : <integer_value>,
"columns" : [list of OrderByColumnSpec],
}
```
#### OrderByColumnSpec
OrderByColumnSpecs indicate how to do order by operations. Each order-by condition can be a `jsonString` or a map of the following form:
```json
{
"dimension" : "<Any dimension or metric name>",
"direction" : <"ascending"|"descending">,
"dimensionOrder" : <"lexicographic"(default)|"alphanumeric"|"strlen"|"numeric">
}
```
If only the dimension is provided (as a JSON string), the default order-by is ascending with lexicographic sorting.
See [Sorting Orders](./sorting-orders.md) for more information on the sorting orders specified by "dimensionOrder".