feat: add system tables index.md (#2051)

Author: BohuTANG

docs/en/sql-reference/00-sql-reference/31-system-tables/_category_.json

@@ -1,6 +1,3 @@
 {
-  "label": "System Tables",
-  "link": {
-    "type": "generated-index"
-  }
+  "label": "System Tables"
 }

docs/en/sql-reference/00-sql-reference/31-system-tables/index.md

@@ -0,0 +1,68 @@
+---
+title: System Tables
+---
+
+# System Tables
+
+Databend provides a set of system tables that contain metadata about your Databend deployment, databases, tables, queries, and system performance. These tables are read-only and are automatically updated by the system.
+
+System tables are organized in the `system` schema and can be queried using standard SQL. They provide valuable information for monitoring, troubleshooting, and understanding your Databend environment.
+
+## Available System Tables
+
+### Database & Table Metadata
+
+| Table | Description |
+|-------|-------------|
+| [system.tables](system-tables.md) | Provides metadata information for all tables including properties, creation time, size, and more. |
+| [system.tables_with_history](system-tables-with-history.md) | Provides historical metadata information for tables, including dropped tables. |
+| [system.databases](system-databases.md) | Contains information about all databases in the system. |
+| [system.databases_with_history](system-databases-with-history.md) | Contains historical information about databases, including dropped databases. |
+| [system.columns](system-columns.md) | Provides information about columns in all tables. |
+| [system.indexes](system-indexes.md) | Contains information about table indexes. |
+| [system.virtual_columns](system-virtual-columns.md) | Lists virtual columns available in the system. |
+
+### Query & Performance
+
+| Table | Description |
+|-------|-------------|
+| [system.query_log](system-query-log.md) | Contains information about executed queries, including performance metrics. |
+| [system.metrics](system-metrics.md) | Contains information about system metric events. |
+| [system.query_cache](system-query-cache.md) | Provides information about the query cache. |
+| [system.locks](system-locks.md) | Contains information about acquired locks in the system. |
+
+### Functions & Settings
+
+| Table | Description |
+|-------|-------------|
+| [system.functions](system-functions.md) | Lists all available built-in functions. |
+| [system.table_functions](system-table-functions.md) | Lists all available table functions. |
+| [system.user_functions](system-user-functions.md) | Contains information about user-defined functions. |
+| [system.settings](system-settings.md) | Contains information about system settings. |
+| [system.configs](system-configs.md) | Contains configuration information for the Databend deployment. |
+
+### System Information
+
+| Table | Description |
+|-------|-------------|
+| [system.build_options](system-build-options.md) | Contains information about build options used to compile Databend. |
+| [system.clusters](system-clusters.md) | Contains information about clusters in the system. |
+| [system.contributors](system-contributors.md) | Lists contributors to the Databend project. |
+| [system.credits](system-credits.md) | Contains information about third-party libraries used in Databend. |
+| [system.caches](system-caches.md) | Provides information about system caches. |
+
+### Utility Tables
+
+| Table | Description |
+|-------|-------------|
+| [system.numbers](system-numbers.md) | A table containing a single column with integers starting from 0, useful for generating test data. |
+| [system.streams](system-streams.md) | Contains information about streams in the system. |
+| [system.temp_tables](system-temp-tables.md) | Contains information about temporary tables. |
+| [system.temp_files](system-temp-files.md) | Contains information about temporary files. |
+
+### Information Schema
+
+| Table | Description |
+|-------|-------------|
+| [information_schema.tables](information-schema-tables.md) | ANSI SQL standard metadata view for tables. |
+