未验证 提交 ba8a65a1 编写于 作者: S Shengliang Guan 提交者: GitHub

Merge pull request #18989 from taosdata/feature/stream

docs(stream)
......@@ -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If some streams are totally outdated, and you do not want it to monitor or process anymore, those streams can be manually dropped and output data will be still kept.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
......
......@@ -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
......
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