ClickHouse/docs/en/operations/system-tables/tables.md

# system.tables {#system-tables}

Contains metadata of each table that the server knows about. Detached tables are not shown in `system.tables`.

This table contains the following columns (the column type is shown in brackets):

-   `database` (String) — The name of the database the table is in.

-   `name` (String) — Table name.

-   `engine` (String) — Table engine name (without parameters).

-   `is_temporary` (UInt8) - Flag that indicates whether the table is temporary.

-   `data_path` (String) - Path to the table data in the file system.

-   `metadata_path` (String) - Path to the table metadata in the file system.

-   `metadata_modification_time` (DateTime) - Time of latest modification of the table metadata.

-   `dependencies_database` (Array(String)) - Database dependencies.

-   `dependencies_table` (Array(String)) - Table dependencies ([MaterializedView](../../engines/table-engines/special/materializedview.md) tables based on the current table).

-   `create_table_query` (String) - The query that was used to create the table.

-   `engine_full` (String) - Parameters of the table engine.

-   `partition_key` (String) - The partition key expression specified in the table.

-   `sorting_key` (String) - The sorting key expression specified in the table.

-   `primary_key` (String) - The primary key expression specified in the table.

-   `sampling_key` (String) - The sampling key expression specified in the table.

-   `storage_policy` (String) - 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(UInt64)) - 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(UInt64)) - 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(UInt64)) - Total number of rows INSERTed since server start.

-   `lifetime_bytes` (Nullable(UInt64)) - Total number of bytes INSERTed since server start.

The `system.tables` table is used in `SHOW TABLES` query implementation.