Update 06-stream.md

docs/zh/07-develop/06-stream.md

@@ -52,7 +52,7 @@ CREATE TABLE d1004 USING meters TAGS ("California.LosAngeles", 3);
 ### 创建流
 
 ```sql
-create stream current_stream into current_stream_output_stb as select _wstart as start, _wend as wend, max(current) as max_current from meters where voltage <= 220 interval (5s);
+create stream current_stream trigger at_once into current_stream_output_stb as select _wstart as wstart, _wend as wend, max(current) as max_current from meters where voltage <= 220 interval (5s);
 ```
 
 ### 写入数据
@@ -70,8 +70,8 @@ insert into d1004 values("2018-10-03 14:38:06.500", 11.50000, 221, 0.35000);
 ### 查询以观察结果
 
 ```sql
-taos> select start, wend, max_current from current_stream_output_stb;
-          start          |          wend           |     max_current      |
+taos> select wstart, wend, max_current from current_stream_output_stb;
+          wstart         |          wend           |     max_current      |
 ===========================================================================
  2018-10-03 14:38:05.000 | 2018-10-03 14:38:10.000 |             10.30000 |
  2018-10-03 14:38:15.000 | 2018-10-03 14:38:20.000 |             12.60000 |
@@ -89,7 +89,7 @@ Query OK, 2 rows in database (0.018762s)
 ### 创建流
 
 ```sql
-create stream power_stream into power_stream_output_stb as select ts, concat_ws(".", location, tbname) as meter_location, current*voltage*cos(phase) as active_power, current*voltage*sin(phase) as reactive_power from meters partition by tbname;
+create stream power_stream trigger at_once into power_stream_output_stb as select ts, concat_ws(".", location, tbname) as meter_location, current*voltage*cos(phase) as active_power, current*voltage*sin(phase) as reactive_power from meters partition by tbname;
 ```
 
 ### 写入数据