This is an automated email from the ASF dual-hosted git repository. jackietien pushed a commit to branch AddLastQueryDoc in repository https://gitbox.apache.org/repos/asf/iotdb.git
commit d2c32b1511ae40e7283d3a1c99322458d10920f0 Author: JackieTien97 <[email protected]> AuthorDate: Mon Sep 5 14:05:32 2022 +0800 Add doc for last query order by timeseries --- docs/UserGuide/Query-Data/Last-Query.md | 18 +++++++++++++++++- docs/zh/UserGuide/Query-Data/Last-Query.md | 18 +++++++++++++++++- 2 files changed, 34 insertions(+), 2 deletions(-) diff --git a/docs/UserGuide/Query-Data/Last-Query.md b/docs/UserGuide/Query-Data/Last-Query.md index d22fd52a39..80134b4087 100644 --- a/docs/UserGuide/Query-Data/Last-Query.md +++ b/docs/UserGuide/Query-Data/Last-Query.md @@ -28,7 +28,7 @@ The last query is to return the most recent data point of the given timeseries i The SQL syntax is defined as: ```sql -select last <Path> [COMMA <Path>]* from < PrefixPath > [COMMA < PrefixPath >]* <WhereClause> +select last <Path> [COMMA <Path>]* from < PrefixPath > [COMMA < PrefixPath >]* <WhereClause> [ORDER BY TIMESERIES (DESC | ASC)?] ``` which means: Query and return the last data points of timeseries prefixPath.path. @@ -68,4 +68,20 @@ IoTDB> select last status, temperature from root.ln.wf01.wt01 where time >= 2017 +-----------------------------+-----------------------------+---------+--------+ Total line number = 2 It costs 0.002s +``` + +## Order By timeseries + +**Example 3:** get the last points of all sensor in root.ln.wf01.wt01, and order the result by the timeseries column desc + +``` +IoTDB> select last * from root.ln.wf01.wt01 order by timeseries desc; ++-----------------------------+-----------------------------+---------+--------+ +| Time| timeseries| value|dataType| ++-----------------------------+-----------------------------+---------+--------+ +|2017-11-07T23:59:00.000+08:00|root.ln.wf01.wt01.temperature|21.067368| DOUBLE| +|2017-11-07T23:59:00.000+08:00| root.ln.wf01.wt01.status| false| BOOLEAN| ++-----------------------------+-----------------------------+---------+--------+ +Total line number = 2 +It costs 0.002s ``` \ No newline at end of file diff --git a/docs/zh/UserGuide/Query-Data/Last-Query.md b/docs/zh/UserGuide/Query-Data/Last-Query.md index 6c657b0dde..2084cc0823 100644 --- a/docs/zh/UserGuide/Query-Data/Last-Query.md +++ b/docs/zh/UserGuide/Query-Data/Last-Query.md @@ -26,7 +26,7 @@ SQL 语法： ```sql -select last <Path> [COMMA <Path>]* from < PrefixPath > [COMMA < PrefixPath >]* <whereClause> +select last <Path> [COMMA <Path>]* from < PrefixPath > [COMMA < PrefixPath >]* <whereClause> [ORDER BY TIMESERIES (DESC | ASC)?] ``` 其含义是：查询时间序列 prefixPath.path 中最近时间戳的数据。 @@ -66,4 +66,20 @@ IoTDB> select last status, temperature from root.ln.wf01.wt01 where time >= 2017 +-----------------------------+-----------------------------+---------+--------+ Total line number = 2 It costs 0.002s +``` + +## 将结果集根据序列名进行排序 + +**示例 3：** 查询 root.ln.wf01.wt01 下所有序列的最新数据点，并按照序列名降序排列。 + +``` +IoTDB> select last * from root.ln.wf01.wt01 order by timeseries desc; ++-----------------------------+-----------------------------+---------+--------+ +| Time| timeseries| value|dataType| ++-----------------------------+-----------------------------+---------+--------+ +|2017-11-07T23:59:00.000+08:00|root.ln.wf01.wt01.temperature|21.067368| DOUBLE| +|2017-11-07T23:59:00.000+08:00| root.ln.wf01.wt01.status| false| BOOLEAN| ++-----------------------------+-----------------------------+---------+--------+ +Total line number = 2 +It costs 0.002s ``` \ No newline at end of file
