docs: dashboard timezone settings and interval keyword

docs/reference/sql/data-types.md

@@ -189,6 +189,44 @@ Supported abbreviations include:
 | us           | microseconds |
 | ns           | nanoseconds  |
 
+#### INTERVAL keyword
+
+In the examples above, we used the cast operation `'{quantity unit}'::INTERVAL` to demonstrate the interval type. In fact, the interval type can also be used with the syntax supported by the `INTERVAL` keyword, though the behavior varies between database dialects:
+
+1. In MySQL, the syntax is `INTERVAL {quantity} {unit}`, where `quantity` can be a number or a string depending on the context. For example:
+```sql
+mysql> SELECT INTERVAL 1 YEAR;
++--------------------------------------------------------------------------------------+
+| IntervalMonthDayNano("IntervalMonthDayNano { months: 12, days: 0, nanoseconds: 0 }") |
++--------------------------------------------------------------------------------------+
+| P1Y0M0DT0H0M0S                                                                       |
++--------------------------------------------------------------------------------------+
+1 row in set (0.01 sec)
+
+mysql> SELECT INTERVAL '1 YEAR 2' MONTH;
++--------------------------------------------------------------------------------------+
+| IntervalMonthDayNano("IntervalMonthDayNano { months: 14, days: 0, nanoseconds: 0 }") |
++--------------------------------------------------------------------------------------+
+| P1Y2M0DT0H0M0S                                                                       |
++--------------------------------------------------------------------------------------+
+1 row in set (0.00 sec)
+```
+
+2. In PostgreSQL and the default GreptimeDB dialect, it is `INTERVAL '{quantity unit}'`, where the INTERVAL keyword is followed by the interval string:
+```sql
+public=> SELECT INTERVAL '1 year';
+ IntervalMonthDayNano("IntervalMonthDayNano { months: 12, days: 0, nanoseconds: 0 }")
+--------------------------------------------------------------------------------------
+ 1 year
+(1 row)
+
+public=> SELECT INTERVAL '1 year 2 month';
+ IntervalMonthDayNano("IntervalMonthDayNano { months: 14, days: 0, nanoseconds: 0 }")
+--------------------------------------------------------------------------------------
+ 1 year 2 mons
+(1 row)
+```
+
 ## JSON Type (Experimental)
 
 :::warning

docs/user-guide/timezone.md

@@ -29,6 +29,10 @@ To configure the time zone for the PostgreSQL client, please refer to the [time
 
 When using the HTTP API, you can specify the time zone through the header parameter. For more information, please refer to the [HTTP API documentation](/user-guide/protocols/http.md#time-zone).
 
+### Dashboard
+
+The dashboard will use the local timezone as the default timezone value. You can change it in the settings menu.
+
 ### Other clients
 
 For other clients, you can change [the default time zone configuration](/user-guide/deployments-administration/configuration.md#default-time-zone-configuration) of GreptimeDB.

i18n/zh/docusaurus-plugin-content-docs/current/reference/sql/data-types.md

@@ -189,6 +189,44 @@ SELECT '-1h5m'::INTERVAL;
 | us     | microseconds |
 | ns     | nanoseconds  |
 
+#### INTERVAL 关键字
+
+在上述示例中，我们使用了 `cast` 类型转换操作 `'{quantity unit}'::INTERVAL` 来演示 interval 类型。实际上，interval 类型也可以使用 `INTERVAL` 关键字支持的语法，不过不同数据库方言之间的行为有所差异：
+
+1. 在 MySQL 中，语法为 `INTERVAL {quantity} {unit}`，其中 `quantity` 可以是数字或字符串，具体取决于上下文。例如：
+```sql
+mysql> SELECT INTERVAL 1 YEAR;
++--------------------------------------------------------------------------------------+
+| IntervalMonthDayNano("IntervalMonthDayNano { months: 12, days: 0, nanoseconds: 0 }") |
++--------------------------------------------------------------------------------------+
+| P1Y0M0DT0H0M0S                                                                       |
++--------------------------------------------------------------------------------------+
+1 row in set (0.01 sec)
+
+mysql> SELECT INTERVAL '1 YEAR 2' MONTH;
++--------------------------------------------------------------------------------------+
+| IntervalMonthDayNano("IntervalMonthDayNano { months: 14, days: 0, nanoseconds: 0 }") |
++--------------------------------------------------------------------------------------+
+| P1Y2M0DT0H0M0S                                                                       |
++--------------------------------------------------------------------------------------+
+1 row in set (0.00 sec)
+```
+
+2. 在 PostgreSQL 和默认的 GreptimeDB 方言中，语法为 `INTERVAL '{quantity unit}'`，即 INTERVAL 关键字后跟 interval 字符串：
+```sql
+public=> SELECT INTERVAL '1 year';
+ IntervalMonthDayNano("IntervalMonthDayNano { months: 12, days: 0, nanoseconds: 0 }")
+--------------------------------------------------------------------------------------
+ 1 year
+(1 row)
+
+public=> SELECT INTERVAL '1 year 2 month';
+ IntervalMonthDayNano("IntervalMonthDayNano { months: 14, days: 0, nanoseconds: 0 }")
+--------------------------------------------------------------------------------------
+ 1 year 2 mons
+(1 row)
+```
+
 ## JSON 类型（实验功能）
 
 :::warning

i18n/zh/docusaurus-plugin-content-docs/current/user-guide/timezone.md

@@ -29,6 +29,10 @@ GreptimeDB 在数据写入或查询时，会根据指定的时区将时间值从
 
 使用 HTTP API 时，你可以通过 header 参数指定时区。有关更多信息，请参阅 [HTTP API 文档](/user-guide/protocols/http.md#时区)。
 
+### Dashboard
+
+Dashboard 将使用本地时区作为默认时区值。您可以在 settings 菜单中更改它。
+
 ### 其他客户端
 
 对于其他客户端，你可以更改 GreptimeDB 的[默认时区配置](/user-guide/deployments-administration/configuration.md#默认时区配置)。