xxq250
/
homework-jianmu
1
0
Fork 0
Code Issues Pull Requests 1 Actions Packages Projects Releases Wiki Activity

Update 14-stream.md

This commit is contained in:
Haojun Liao 2023-04-24 19:00:07 +08:00 committed by GitHub
parent 809fe165e7
commit 817dc57611
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
1 changed files with 26 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

26
docs/zh/12-taos-sql/14-stream.md
View File

@ -213,3 +213,29 @@ DELETE_MARK time
```
DELETE_MARK用于删除缓存的窗口状态，也就是删除流计算的中间结果。如果不设置，默认值是10年
T = 最新事件时间 - DELETE_MARK
## 流式计算支持的函数
1. 所有的单行函数均可用于流计算中。
2. 以下 19 个聚合函数不能在创建流计算的 SQL 语句中使用
```
leastsquares
percentile
top
bottom
elapsed
interp
derivative
irate
twa
histogram
diff
statecount
stateduration
csum
mavg
sample
tail
unique
mode
```