system.columns
Contains information about columns of tables.
SELECT * FROM system.columns;
+--------------------------+----------+--------------+-------------------+-------------+
| name | database | table | data_type | is_nullable |
+--------------------------+----------+--------------+-------------------+-------------+
| port | system | clusters | SMALLINT UNSIGNED | 0 |
| host | system | clusters | VARCHAR | 0 |
| name | system | clusters | VARCHAR | 0 |
| is_nullable | system | columns | BOOLEAN | 0 |
| data_type | system | columns | VARCHAR | 0 |
| table | system | columns | VARCHAR | 0 |
| database | system | columns | VARCHAR | 0 |
| name | system | columns | VARCHAR | 0 |
| group | system | configs | VARCHAR | 0 |
| name | system | configs | VARCHAR | 0 |
| value | system | configs | VARCHAR | 0 |
| description | system | configs | VARCHAR | 0 |
| name | system | contributors | VARCHAR | 0 |
| name | system | credits | VARCHAR | 0 |
| version | system | credits | VARCHAR | 0 |
| license | system | credits | VARCHAR | 0 |
| name | system | databases | VARCHAR | 0 |
| Comment | system | engines | VARCHAR | 0 |
| Engine | system | engines | VARCHAR | 0 |
| example | system | functions | VARCHAR | 0 |
| syntax | system | functions | VARCHAR | 0 |
| description | system | functions | VARCHAR | 0 |
| category | system | functions | VARCHAR | 0 |
| definition | system | functions | VARCHAR | 0 |
| is_aggregate | system | functions | BOOLEAN | 0 |
| is_builtin | system | functions | BOOLEAN | 0 |
| name | system | functions | VARCHAR | 0 |
| value | system | metrics | VARCHAR | 0 |
| labels | system | metrics | VARCHAR | 0 |
| kind | system | metrics | VARCHAR | 0 |
| metric | system | metrics | VARCHAR | 0 |
| dummy | system | one | TINYINT UNSIGNED | 0 |
| id | system | processes | VARCHAR | 0 |
| scan_progress_read_bytes | system | processes | BIGINT UNSIGNED | 1 |
| scan_progress_read_rows | system | processes | BIGINT UNSIGNED | 1 |
| dal_metrics_write_bytes | system | processes | BIGINT UNSIGNED | 1 |
| dal_metrics_read_bytes | system | processes | BIGINT UNSIGNED | 1 |
| memory_usage | system | processes | BIGINT | 0 |
| extra_info | system | processes | VARCHAR | 1 |
| database | system | processes | VARCHAR | 0 |
| state | system | processes | VARCHAR | 0 |
| user | system | processes | VARCHAR | 1 |
| host | system | processes | VARCHAR | 1 |
| type | system | processes | VARCHAR | 0 |
| scan_partitions | system | query_log | BIGINT UNSIGNED | 0 |
| written_io_bytes_cost_ms | system | query_log | BIGINT UNSIGNED | 0 |
| extra | system | query_log | VARCHAR | 0 |
| session_settings | system | query_log | VARCHAR | 0 |
| server_version | system | query_log | VARCHAR | 0 |
| stack_trace | system | query_log | VARCHAR | 0 |
| exception_text | system | query_log | VARCHAR | 0 |
| exception_code | system | query_log | INT | 0 |
| client_address | system | query_log | VARCHAR | 0 |
| client_info | system | query_log | VARCHAR | 0 |
| memory_usage | system | query_log | BIGINT UNSIGNED | 0 |
| cpu_usage | system | query_log | INT UNSIGNED | 0 |
| result_bytes | system | query_log | BIGINT UNSIGNED | 0 |
| result_rows | system | query_log | BIGINT UNSIGNED | 0 |
| total_partitions | system | query_log | BIGINT UNSIGNED | 0 |
| log_type | system | query_log | TINYINT | 0 |
| handler_type | system | query_log | VARCHAR | 0 |
| tenant_id | system | query_log | VARCHAR | 0 |
| cluster_id | system | query_log | VARCHAR | 0 |
| sql_user | system | query_log | VARCHAR | 0 |
| sql_user_quota | system | query_log | VARCHAR | 0 |
| sql_user_privileges | system | query_log | VARCHAR | 0 |
| query_id | system | query_log | VARCHAR | 0 |
| query_kind | system | query_log | VARCHAR | 0 |
| query_text | system | query_log | VARCHAR | 0 |
| event_date | system | query_log | DATE | 0 |
| event_time | system | query_log | TIMESTAMP(3) | 0 |
| current_database | system | query_log | VARCHAR | 0 |
| databases | system | query_log | VARCHAR | 0 |
| tables | system | query_log | VARCHAR | 0 |
| columns | system | query_log | VARCHAR | 0 |
| projections | system | query_log | VARCHAR | 0 |
| written_rows | system | query_log | BIGINT UNSIGNED | 0 |
| written_bytes | system | query_log | BIGINT UNSIGNED | 0 |
| written_io_bytes | system | query_log | BIGINT UNSIGNED | 0 |
| scan_io_bytes_cost_ms | system | query_log | BIGINT UNSIGNED | 0 |
| scan_rows | system | query_log | BIGINT UNSIGNED | 0 |
| scan_bytes | system | query_log | BIGINT UNSIGNED | 0 |
| scan_io_bytes | system | query_log | BIGINT UNSIGNED | 0 |
| inherited_roles | system | roles | BIGINT UNSIGNED | 0 |
| name | system | roles | VARCHAR | 0 |
| name | system | settings | VARCHAR | 0 |
| default | system | settings | VARCHAR | 0 |
| level | system | settings | VARCHAR | 0 |
| description | system | settings | VARCHAR | 0 |
| type | system | settings | VARCHAR | 0 |
| value | system | settings | VARCHAR | 0 |
| num_rows | system | tables | BIGINT UNSIGNED | 1 |
| data_size | system | tables | BIGINT UNSIGNED | 1 |
| database | system | tables | VARCHAR | 0 |
| name | system | tables | VARCHAR | 0 |
| engine | system | tables | VARCHAR | 0 |
| created_on | system | tables | VARCHAR | 0 |
| index_size | system | tables | BIGINT UNSIGNED | 1 |
| data_compressed_size | system | tables | BIGINT UNSIGNED | 1 |
| v | system | tracing | BIGINT | 0 |
| name | system | tracing | VARCHAR | 0 |
| msg | system | tracing | VARCHAR | 0 |
| level | system | tracing | TINYINT | 0 |
| hostname | system | tracing | VARCHAR | 0 |
| pid | system | tracing | BIGINT | 0 |
| time | system | tracing | VARCHAR | 0 |
| name | system | users | VARCHAR | 0 |
| hostname | system | users | VARCHAR | 0 |
| auth_type | system | users | VARCHAR | 0 |
| auth_string | system | users | VARCHAR | 0 |
| creation_time | system | warehouses | TIMESTAMP(0) | 0 |
| name | system | warehouses | VARCHAR | 0 |
| tenant_id | system | warehouses | VARCHAR | 0 |
| id | system | warehouses | VARCHAR | 0 |
| size | system | warehouses | VARCHAR | 0 |
+--------------------------+----------+--------------+-------------------+-------------+