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new f53029b133 Add doc for last query order by timeseries (#7232)
f53029b133 is described below
commit f53029b1336c60954bc4378c407a9eb608ce9aeb
Author: Jackie Tien <[email protected]>
AuthorDate: Mon Sep 5 14:31:26 2022 +0800
Add doc for last query order by timeseries (#7232)
---
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
