docs: OR REPLACE

docs/user-guide/continuous-aggregation/manage-flow.md

@@ -65,15 +65,18 @@ AS
 ``` -->
 
 ```sql
-CREATE FLOW [ IF NOT EXISTS ] <flow-name>
+CREATE [ OR REPLACE ] FLOW [ IF NOT EXISTS ] <flow-name>
 SINK TO <sink-table-name>
 [ EXPIRE AFTER <expr> ]
 [ COMMENT '<string>' ]
 AS 
 <SQL>;
 ```
 
-<!-- When `OR REPLACE` is specified, if a flow with the same name already exists, it will be updated to the new one. Notice that this only affects the flow task itself, and both source and sink tables will not be changed. -->
+When `OR REPLACE` is specified, any existing flow with the same name will be updated to the new version. It's important to note that this only affects the flow task itself; the source and sink tables will remain unchanged.
+
+Conversely, when `IF NOT EXISTS` is specified, the command will have no effect if the flow already exists, rather than reporting an error. Additionally, please note that `OR REPLACE` cannot be used in conjunction with `IF NOT EXISTS`.
+
 
 - `flow-name` is an unique identifier in the catalog level.
 - `sink-table-name` is the table name where the materialized aggregated data is stored.

i18n/zh/docusaurus-plugin-content-docs/current/user-guide/continuous-aggregation/manage-flow.md

@@ -56,14 +56,16 @@ sink 表包含列 `sensor_id`、`loc`、`max_temp`、`time_window` 和 `update_a
 创建 flow 的语法是：
 
 ```sql
-CREATE FLOW [ IF NOT EXISTS ] <flow-name>
+CREATE [ OR REPLACE ] FLOW [ IF NOT EXISTS ] <flow-name>
 SINK TO <sink-table-name>
 [ EXPIRE AFTER <expr> ]
 [ COMMENT '<string>' ]
 AS 
 <SQL>;
 ```
 
+当指定 `OR REPLACE` 时，如果已经存在同名的 flow，它将被更新为新 flow。请注意，这仅影响 flow 任务本身，source 表和 sink 表将不会被更改。当指定 `IF NOT EXISTS` 时，如果 flow 已经存在，它将不执行任何操作，而不是报告错误。还需要注意的是，`OR REPLACE` 不能与 `IF NOT EXISTS` 一起使用。
+
 - `flow-name` 是目录级别的唯一标识符。
 - `sink-table-name` 是存储聚合数据的表名。
   它可以是一个现有的表或一个新表。如果目标表不存在，`flow` 将创建目标表。