docs: add SHOW ONLINE NODES SQL reference

docs/cn/sql-reference/10-sql-commands/00-ddl/19-warehouse/index.md

@@ -20,6 +20,7 @@ Databend Cloud 计算集群相关的 SQL 命令。
 | [CREATE WAREHOUSE](create-warehouse.md) | 创建计算集群 |
 | [USE WAREHOUSE](use-warehouse.md) | 切换当前会话的计算集群 |
 | [SHOW WAREHOUSES](show-warehouses.md) | 查看计算集群列表 |
+| [SHOW ONLINE NODES](show-online-nodes.md) | 查看系统管理的在线查询节点 |
 | [ALTER WAREHOUSE](alter-warehouse.md) | 暂停、恢复或修改计算集群配置 |
 | [DROP WAREHOUSE](drop-warehouse.md) | 删除计算集群 |
 | [REPLACE WAREHOUSE](replace-warehouse.md) | 重建计算集群 |

docs/cn/sql-reference/10-sql-commands/00-ddl/19-warehouse/show-online-nodes.md

@@ -0,0 +1,35 @@
+---
+title: SHOW ONLINE NODES
+sidebar_position: 7
+---
+
+列出当前 tenant 可见的在线查询节点。
+
+:::note
+此命令依赖 system management 功能，并需要企业版许可证。
+:::
+
+## 语法
+
+```sql
+SHOW ONLINE NODES
+```
+
+## 输出
+
+`SHOW ONLINE NODES` 返回以下列：
+
+| 列名 | 说明 |
+|--------|-------------|
+| `id` | 节点标识 |
+| `type` | 节点类型，例如 `SelfManaged` 或 `SystemManaged` |
+| `group` | 节点组 |
+| `warehouse` | 计算集群标识 |
+| `cluster` | 集群标识 |
+| `version` | 二进制版本 |
+
+## 示例
+
+```sql
+SHOW ONLINE NODES;
+```

docs/en/sql-reference/10-sql-commands/00-ddl/19-warehouse/index.md

@@ -55,6 +55,7 @@ Tags are returned in API responses and visible through `SHOW WAREHOUSES`.
 | [CREATE WAREHOUSE](create-warehouse.md) | Creates a new warehouse                           |
 | [USE WAREHOUSE](use-warehouse.md)       | Sets the current warehouse for the session        |
 | [SHOW WAREHOUSES](show-warehouses.md)   | Lists all warehouses with optional filtering      |
+| [SHOW ONLINE NODES](show-online-nodes.md) | Lists online query nodes managed by the system |
 | [ALTER WAREHOUSE](alter-warehouse.md)   | Suspends, resumes, or modifies warehouse settings |
 | [DROP WAREHOUSE](drop-warehouse.md)     | Removes a warehouse                               |
 | [QUERY_HISTORY](query-history.md)       | Inspects query logs for a warehouse               |

docs/en/sql-reference/10-sql-commands/00-ddl/19-warehouse/show-online-nodes.md

@@ -0,0 +1,35 @@
+---
+title: SHOW ONLINE NODES
+sidebar_position: 7
+---
+
+Lists online query nodes visible to the current tenant.
+
+:::note
+This command requires system management support and an enterprise license.
+:::
+
+## Syntax
+
+```sql
+SHOW ONLINE NODES
+```
+
+## Output
+
+`SHOW ONLINE NODES` returns the following columns:
+
+| Column | Description |
+|--------|-------------|
+| `id` | Node identifier |
+| `type` | Node type, such as `SelfManaged` or `SystemManaged` |
+| `group` | Node group |
+| `warehouse` | Warehouse identifier |
+| `cluster` | Cluster identifier |
+| `version` | Binary version |
+
+## Example
+
+```sql
+SHOW ONLINE NODES;
+```