# tables {#system-tables} Contains metadata of each table that the server knows about. [Detached](../../sql-reference/statements/detach.md) tables are not shown in `system.tables`. [Temporary tables](../../sql-reference/statements/create/table.md#temporary-tables) are visible in the `system.tables` only in those session where they have been created. They are shown with the empty `database` field and with the `is_temporary` flag switched on. Columns: - `database` ([String](../../sql-reference/data-types/string.md)) — The name of the database the table is in. - `name` ([String](../../sql-reference/data-types/string.md)) — Table name. - `engine` ([String](../../sql-reference/data-types/string.md)) — Table engine name (without parameters). - `is_temporary` ([UInt8](../../sql-reference/data-types/int-uint.md)) - Flag that indicates whether the table is temporary. - `data_path` ([String](../../sql-reference/data-types/string.md)) - Path to the table data in the file system. - `metadata_path` ([String](../../sql-reference/data-types/string.md)) - Path to the table metadata in the file system. - `metadata_modification_time` ([DateTime](../../sql-reference/data-types/datetime.md)) - Time of latest modification of the table metadata. - `dependencies_database` ([Array](../../sql-reference/data-types/array.md)([String](../../sql-reference/data-types/string.md))) - Database dependencies. - `dependencies_table` ([Array](../../sql-reference/data-types/array.md)([String](../../sql-reference/data-types/string.md))) - Table dependencies ([MaterializedView](../../engines/table-engines/special/materializedview.md) tables based on the current table). - `create_table_query` ([String](../../sql-reference/data-types/string.md)) - The query that was used to create the table. - `engine_full` ([String](../../sql-reference/data-types/string.md)) - Parameters of the table engine. - `as_select` ([String](../../sql-reference/data-types/string.md)) - `SELECT` query for view. - `partition_key` ([String](../../sql-reference/data-types/string.md)) - The partition key expression specified in the table. - `sorting_key` ([String](../../sql-reference/data-types/string.md)) - The sorting key expression specified in the table. - `primary_key` ([String](../../sql-reference/data-types/string.md)) - The primary key expression specified in the table. - `sampling_key` ([String](../../sql-reference/data-types/string.md)) - The sampling key expression specified in the table. - `storage_policy` ([String](../../sql-reference/data-types/string.md)) - The storage policy: - [MergeTree](../../engines/table-engines/mergetree-family/mergetree.md#table_engine-mergetree-multiple-volumes) - [Distributed](../../engines/table-engines/special/distributed.md#distributed) - `total_rows` ([Nullable](../../sql-reference/data-types/nullable.md)([UInt64](../../sql-reference/data-types/int-uint.md))) - Total number of rows, if it is possible to quickly determine exact number of rows in the table, otherwise `NULL` (including underying `Buffer` table). - `total_bytes` ([Nullable](../../sql-reference/data-types/nullable.md)([UInt64](../../sql-reference/data-types/int-uint.md))) - Total number of bytes, if it is possible to quickly determine exact number of bytes for the table on storage, otherwise `NULL` (does not includes any underlying storage). - If the table stores data on disk, returns used space on disk (i.e. compressed). - If the table stores data in memory, returns approximated number of used bytes in memory. - `lifetime_rows` ([Nullable](../../sql-reference/data-types/nullable.md)([UInt64](../../sql-reference/data-types/int-uint.md))) - Total number of rows INSERTed since server start (only for `Buffer` tables). - `lifetime_bytes` ([Nullable](../../sql-reference/data-types/nullable.md)([UInt64](../../sql-reference/data-types/int-uint.md))) - Total number of bytes INSERTed since server start (only for `Buffer` tables). - `comment` ([String](../../sql-reference/data-types/string.md)) - The comment for the table. - `has_own_data` ([UInt8](../../sql-reference/data-types/int-uint.md)) — Flag that indicates whether the table itself stores some data on disk or only accesses some other source. The `system.tables` table is used in `SHOW TABLES` query implementation. **Example** ```sql SELECT * FROM system.tables LIMIT 2 FORMAT Vertical; ``` ```text Row 1: ────── database: base name: t1 uuid: 81b1c20a-b7c6-4116-a2ce-7583fb6b6736 engine: MergeTree is_temporary: 0 data_paths: ['/var/lib/clickhouse/store/81b/81b1c20a-b7c6-4116-a2ce-7583fb6b6736/'] metadata_path: /var/lib/clickhouse/store/461/461cf698-fd0b-406d-8c01-5d8fd5748a91/t1.sql metadata_modification_time: 2021-01-25 19:14:32 dependencies_database: [] dependencies_table: [] create_table_query: CREATE TABLE base.t1 (`n` UInt64) ENGINE = MergeTree ORDER BY n SETTINGS index_granularity = 8192 engine_full: MergeTree ORDER BY n SETTINGS index_granularity = 8192 as_select: SELECT database AS table_catalog partition_key: sorting_key: n primary_key: n sampling_key: storage_policy: default total_rows: 1 total_bytes: 99 lifetime_rows: ᴺᵁᴸᴸ lifetime_bytes: ᴺᵁᴸᴸ comment: has_own_data: 0 Row 2: ────── database: default name: 53r93yleapyears uuid: 00000000-0000-0000-0000-000000000000 engine: MergeTree is_temporary: 0 data_paths: ['/var/lib/clickhouse/data/default/53r93yleapyears/'] metadata_path: /var/lib/clickhouse/metadata/default/53r93yleapyears.sql metadata_modification_time: 2020-09-23 09:05:36 dependencies_database: [] dependencies_table: [] create_table_query: CREATE TABLE default.`53r93yleapyears` (`id` Int8, `febdays` Int8) ENGINE = MergeTree ORDER BY id SETTINGS index_granularity = 8192 engine_full: MergeTree ORDER BY id SETTINGS index_granularity = 8192 as_select: SELECT name AS catalog_name partition_key: sorting_key: id primary_key: id sampling_key: storage_policy: default total_rows: 2 total_bytes: 155 lifetime_rows: ᴺᵁᴸᴸ lifetime_bytes: ᴺᵁᴸᴸ comment: has_own_data: 0 ```