diff --git a/docs/en/12-taos-sql/14-stream.md b/docs/en/12-taos-sql/14-stream.md index 8c81dcaeef..07db5f4877 100644 --- a/docs/en/12-taos-sql/14-stream.md +++ b/docs/en/12-taos-sql/14-stream.md @@ -75,6 +75,21 @@ Normally a stream does not process data already or being written into source tab create stream if not exists s1 fill_history 1 into st1 as select count(*) from t1 interval(10s) ``` +Combining fill_history option and where clause, stream can processing data of specific time range. For example, only process data after a past time. (In this case, 2020-01-30) + +```sql +create stream if not exists s1 fill_history 1 into st1 as select count(*) from t1 where ts > timestamp '2020-01-30' interval(10s) +``` + +As another example, only processing data starting from some past time, and ending at some future time. + +```sql +create stream if not exists s1 fill_history 1 into st1 as select count(*) from t1 where ts > timestamp '2020-01-30' and ts < timestamp '2023-01-01 '> interval(10s) +``` + +If some streams are totally outdated, and you do not want it to monitor or process anymore, those streams can be manually dropped and output data will be still kept. + + ## Delete a Stream ```sql diff --git a/docs/zh/12-taos-sql/14-stream.md b/docs/zh/12-taos-sql/14-stream.md index 1e6be13639..6c18c41f0c 100644 --- a/docs/zh/12-taos-sql/14-stream.md +++ b/docs/zh/12-taos-sql/14-stream.md @@ -76,6 +76,20 @@ PARTITION 子句中,为 tbname 定义了一个别名 tname, 在PARTITION 子 create stream if not exists s1 fill_history 1 into st1 as select count(*) from t1 interval(10s) ``` +结合 fill_history 1 选项,可以实现只处理特定历史时间范围的数据,例如:只处理某历史时刻(2020年1月30日)之后的数据 + +```sql +create stream if not exists s1 fill_history 1 into st1 as select count(*) from t1 where ts > timestamp '2020-01-30' interval(10s) +``` + +再如,仅处理某时间段内的数据,结束时间可以是未来时间 + +```sql +create stream if not exists s1 fill_history 1 into st1 as select count(*) from t1 where ts > timestamp '2020-01-30' and ts < timestamp '2023-01-01 '> interval(10s) +``` + +如果该流任务已经彻底过期,并且您不再想让它检测或处理数据,您可以手动删除它,被计算出的数据仍会被保留。 + ## 删除流式计算 ```sql