fix: add partition by examples

docs/en/12-taos-sql/12-distinguished.md

@@ -16,7 +16,10 @@ When you query a supertable, you may need to partition the supertable by some di
 PARTITION BY part_list
 ```
 
-part_list can be any scalar expression, such as a column, constant, scalar function, or a combination of the preceding items.
+part_list can be any scalar expression, such as a column, constant, scalar function, or a combination of the preceding items. For example, grouping data by label location, taking the average voltage within each group.
+```sql
+select avg(voltage) from meters partition by location
+```
 
 A PARTITION BY clause is processed as follows:
 
@@ -28,7 +31,10 @@ A PARTITION BY clause is processed as follows:
 select max(current) from meters partition by location interval(10m)
 ```
 
-The most common usage of PARTITION BY is partitioning the data in subtables by tags then perform computation when querying data in a supertable. More specifically, `PARTITION BY TBNAME` partitions the data of each subtable into a single timeline, and this method facilitates the statistical analysis in many use cases of processing timeseries data.
+The most common usage of PARTITION BY is partitioning the data in subtables by tags then perform computation when querying data in a supertable. More specifically, `PARTITION BY TBNAME` partitions the data of each subtable into a single timeline, and this method facilitates the statistical analysis in many use cases of processing timeseries data. For example, calculate the average voltage of each meter every 10 minutes£º
+```sql
+select avg(voltage) from meters partition by tbname interval(10m)
+```
 
 ## Windowed Queries
 

docs/zh/12-taos-sql/12-distinguished.md

@@ -16,7 +16,11 @@ TDengine 提供的特色查询包括数据切分查询和时间窗口切分查
 PARTITION BY part_list
 ```
 
-part_list 可以是任意的标量表达式，包括列、常量、标量函数和它们的组合。
+part_list 可以是任意的标量表达式，包括列、常量、标量函数和它们的组合。例如，将数据按标签 location 进行分组，取每个分组内的电压平均值：
+```sql
+select avg(voltage) from meters partition by location
+```
+
 
 TDengine 按如下方式处理数据切分子句：
 
@@ -27,7 +31,11 @@ TDengine 按如下方式处理数据切分子句：
 ```sql
 select max(current) from meters partition by location interval(10m)
 ```
-数据切分子句最常见的用法就是在超级表查询中，按标签将子表数据进行切分，然后分别进行计算。特别是 PARTITION BY TBNAME 用法，它将每个子表的数据独立出来，形成一条条独立的时间序列，极大的方便了各种时序场景的统计分析。
+数据切分子句最常见的用法就是在超级表查询中，按标签将子表数据进行切分，然后分别进行计算。特别是 PARTITION BY TBNAME 用法，它将每个子表的数据独立出来，形成一条条独立的时间序列，极大的方便了各种时序场景的统计分析。例如，统计每个电表每 10 分钟内的电压平均值：
+```sql
+select avg(voltage) from meters partition by tbname interval(10m)
+```
+
 
 ## 窗口切分查询