ClickHouse/docs/en/sql-reference/statements/show.md

Ignoring revisions in .git-blame-ignore-revs. Click here to bypass and see the normal blame view.

576 lines
16 KiB
Markdown
Raw Normal View History

2020-04-03 13:23:32 +00:00
---
2022-08-28 14:53:34 +00:00
slug: /en/sql-reference/statements/show
sidebar_position: 37
sidebar_label: SHOW
2020-04-03 13:23:32 +00:00
---
2022-06-02 10:55:18 +00:00
# SHOW Statements
2023-04-13 12:27:48 +00:00
## SHOW CREATE TABLE | DICTIONARY | VIEW | DATABASE
2020-03-20 10:10:48 +00:00
``` sql
2023-04-13 12:27:48 +00:00
SHOW [CREATE] [TEMPORARY] TABLE|DICTIONARY|VIEW|DATABASE [db.]table|view [INTO OUTFILE filename] [FORMAT format]
```
2023-04-13 11:06:36 +00:00
Returns a single column of type String containing the CREATE query used for creating the specified object.
2023-04-13 12:27:48 +00:00
`SHOW TABLE t` and `SHOW DATABASE db` have the same meaning as `SHOW CREATE TABLE|DATABASE t|db`, but `SHOW t` and `SHOW db` are not supported.
2023-04-12 14:01:21 +00:00
Note that if you use this statement to get `CREATE` query of system tables, you will get a *fake* query, which only declares table structure, but cannot be used to create table.
2022-06-02 10:55:18 +00:00
## SHOW DATABASES
Prints a list of all databases.
```sql
SHOW DATABASES [[NOT] LIKE | ILIKE '<pattern>'] [LIMIT <N>] [INTO OUTFILE filename] [FORMAT format]
```
This statement is identical to the query:
```sql
SELECT name FROM system.databases [WHERE name [NOT] LIKE | ILIKE '<pattern>'] [LIMIT <N>] [INTO OUTFILE filename] [FORMAT format]
```
**Examples**
Getting database names, containing the symbols sequence 'de' in their names:
2020-03-20 10:10:48 +00:00
``` sql
SHOW DATABASES LIKE '%de%'
```
Result:
``` text
┌─name────┐
│ default │
└─────────┘
```
Getting database names, containing symbols sequence 'de' in their names, in the case insensitive manner:
``` sql
SHOW DATABASES ILIKE '%DE%'
```
Result:
``` text
┌─name────┐
│ default │
└─────────┘
```
Getting database names, not containing the symbols sequence 'de' in their names:
``` sql
SHOW DATABASES NOT LIKE '%de%'
```
Result:
``` text
┌─name───────────────────────────┐
│ _temporary_and_external_tables │
│ system │
│ test │
│ tutorial │
└────────────────────────────────┘
```
Getting the first two rows from database names:
``` sql
SHOW DATABASES LIMIT 2
```
Result:
``` text
┌─name───────────────────────────┐
│ _temporary_and_external_tables │
│ default │
└────────────────────────────────┘
```
**See also**
- [CREATE DATABASE](https://clickhouse.com/docs/en/sql-reference/statements/create/database/#query-language-create-database)
2022-06-02 10:55:18 +00:00
## SHOW PROCESSLIST
2020-03-20 10:10:48 +00:00
``` sql
SHOW PROCESSLIST [INTO OUTFILE filename] [FORMAT format]
```
Outputs the content of the [system.processes](../../operations/system-tables/processes.md#system_tables-processes) table, that contains a list of queries that is being processed at the moment, excepting `SHOW PROCESSLIST` queries.
The `SELECT * FROM system.processes` query returns data about all the current queries.
Tip (execute in the console):
2020-03-20 10:10:48 +00:00
``` bash
$ watch -n1 "clickhouse-client --query='SHOW PROCESSLIST'"
```
2022-06-02 10:55:18 +00:00
## SHOW TABLES
Displays a list of tables.
```sql
SHOW [FULL] [TEMPORARY] TABLES [{FROM | IN} <db>] [[NOT] LIKE | ILIKE '<pattern>'] [LIMIT <N>] [INTO OUTFILE <filename>] [FORMAT <format>]
```
If the `FROM` clause is not specified, the query returns the list of tables from the current database.
This statement is identical to the query:
```sql
SELECT name FROM system.tables [WHERE name [NOT] LIKE | ILIKE '<pattern>'] [LIMIT <N>] [INTO OUTFILE <filename>] [FORMAT <format>]
```
**Examples**
Getting table names, containing the symbols sequence 'user' in their names:
2020-03-20 10:10:48 +00:00
``` sql
SHOW TABLES FROM system LIKE '%user%'
```
Result:
``` text
┌─name─────────────┐
│ user_directories │
│ users │
└──────────────────┘
```
Getting table names, containing sequence 'user' in their names, in the case insensitive manner:
2020-03-20 10:10:48 +00:00
``` sql
SHOW TABLES FROM system ILIKE '%USER%'
```
2020-03-20 10:10:48 +00:00
Result:
``` text
┌─name─────────────┐
│ user_directories │
│ users │
└──────────────────┘
```
Getting table names, not containing the symbol sequence 's' in their names:
``` sql
SHOW TABLES FROM system NOT LIKE '%s%'
```
Result:
``` text
┌─name─────────┐
│ metric_log │
│ metric_log_0 │
│ metric_log_1 │
└──────────────┘
```
Getting the first two rows from table names:
``` sql
SHOW TABLES FROM system LIMIT 2
```
Result:
2020-03-20 10:10:48 +00:00
``` text
┌─name───────────────────────────┐
│ aggregate_function_combinators │
│ asynchronous_metric_log │
└────────────────────────────────┘
```
**See also**
- [Create Tables](https://clickhouse.com/docs/en/getting-started/tutorial/#create-tables)
- [SHOW CREATE TABLE](https://clickhouse.com/docs/en/sql-reference/statements/show/#show-create-table)
## SHOW COLUMNS
Displays a list of columns
```sql
SHOW [EXTENDED] [FULL] COLUMNS {FROM | IN} <table> [{FROM | IN} <db>] [{[NOT] {LIKE | ILIKE} '<pattern>' | WHERE <expr>}] [LIMIT <N>] [INTO
OUTFILE <filename>] [FORMAT <format>]
```
The database and table name can be specified in abbreviated form as `<db>.<table>`, i.e. `FROM tab FROM db` and `FROM db.tab` are
equivalent. If no database is specified, the query returns the list of columns from the current database.
The optional keyword `EXTENDED` currently has no effect, it only exists for MySQL compatibility.
The optional keyword `FULL` causes the output to include the collation, comment and privilege columns.
`SHOW COLUMNS` produces a result table with the following structure:
- field - The name of the column (String)
- type - The column data type (String)
- null - If the column data type is Nullable (UInt8)
- key - `PRI` if the column is part of the primary key, `SOR` if the column is part of the sorting key, empty otherwise (String)
- default - Default expression of the column if it is of type `ALIAS`, `DEFAULT`, or `MATERIALIZED`, otherwise `NULL`. (Nullable(String))
- extra - Additional information, currently unused (String)
2023-03-31 13:53:52 +00:00
- collation - (only if `FULL` keyword was specified) Collation of the column, always `NULL` because ClickHouse has no per-column collations (Nullable(String))
- comment - (only if `FULL` keyword was specified) Comment on the column (String)
- privilege - (only if `FULL` keyword was specified) The privilege you have on this column, currently not available (String)
**Examples**
Getting information about all columns in table 'order' starting with 'delivery_':
```sql
SHOW COLUMNS FROM 'orders' LIKE 'delivery_%'
```
Result:
``` text
┌─field───────────┬─type─────┬─null─┬─key─────┬─default─┬─extra─┐
│ delivery_date │ DateTime │ 0 │ PRI SOR │ ᴺᵁᴸᴸ │ │
│ delivery_status │ Bool │ 0 │ │ ᴺᵁᴸᴸ │ │
└─────────────────┴──────────┴──────┴─────────┴─────────┴───────┘
```
**See also**
2023-04-19 16:10:51 +00:00
- [system.columns](https://clickhouse.com/docs/en/operations/system-tables/columns)
2022-06-02 10:55:18 +00:00
## SHOW DICTIONARIES
2023-03-18 02:45:43 +00:00
Displays a list of [Dictionaries](../../sql-reference/dictionaries/index.md).
2020-03-20 10:10:48 +00:00
``` sql
SHOW DICTIONARIES [FROM <db>] [LIKE '<pattern>'] [LIMIT <N>] [INTO OUTFILE <filename>] [FORMAT <format>]
```
If the `FROM` clause is not specified, the query returns the list of dictionaries from the current database.
You can get the same results as the `SHOW DICTIONARIES` query in the following way:
2020-03-20 10:10:48 +00:00
``` sql
SELECT name FROM system.dictionaries WHERE database = <db> [AND name LIKE <pattern>] [LIMIT <N>] [INTO OUTFILE <filename>] [FORMAT <format>]
```
**Examples**
The following query selects the first two rows from the list of tables in the `system` database, whose names contain `reg`.
2020-03-20 10:10:48 +00:00
``` sql
SHOW DICTIONARIES FROM db LIKE '%reg%' LIMIT 2
```
2020-03-20 10:10:48 +00:00
``` text
┌─name─────────┐
│ regions │
│ region_names │
└──────────────┘
```
2022-06-02 10:55:18 +00:00
## SHOW GRANTS
Shows privileges for a user.
**Syntax**
``` sql
2021-01-23 13:35:26 +00:00
SHOW GRANTS [FOR user1 [, user2 ...]]
```
If user is not specified, the query returns privileges for the current user.
2022-06-02 10:55:18 +00:00
## SHOW CREATE USER
Shows parameters that were used at a [user creation](../../sql-reference/statements/create/user.md).
2021-05-27 19:44:11 +00:00
`SHOW CREATE USER` does not output user passwords.
**Syntax**
``` sql
2021-01-26 22:40:14 +00:00
SHOW CREATE USER [name1 [, name2 ...] | CURRENT_USER]
```
2022-06-02 10:55:18 +00:00
## SHOW CREATE ROLE
Shows parameters that were used at a [role creation](../../sql-reference/statements/create/role.md).
**Syntax**
``` sql
2021-01-26 22:40:14 +00:00
SHOW CREATE ROLE name1 [, name2 ...]
```
2022-06-02 10:55:18 +00:00
## SHOW CREATE ROW POLICY
Shows parameters that were used at a [row policy creation](../../sql-reference/statements/create/row-policy.md).
**Syntax**
``` sql
2021-01-26 22:40:14 +00:00
SHOW CREATE [ROW] POLICY name ON [database1.]table1 [, [database2.]table2 ...]
```
2022-06-02 10:55:18 +00:00
## SHOW CREATE QUOTA
Shows parameters that were used at a [quota creation](../../sql-reference/statements/create/quota.md).
**Syntax**
``` sql
2021-01-26 22:40:14 +00:00
SHOW CREATE QUOTA [name1 [, name2 ...] | CURRENT]
```
2022-06-02 10:55:18 +00:00
## SHOW CREATE SETTINGS PROFILE
Shows parameters that were used at a [settings profile creation](../../sql-reference/statements/create/settings-profile.md).
**Syntax**
``` sql
2021-01-26 22:40:14 +00:00
SHOW CREATE [SETTINGS] PROFILE name1 [, name2 ...]
```
2022-06-02 10:55:18 +00:00
## SHOW USERS
2023-03-18 02:45:43 +00:00
Returns a list of [user account](../../guides/sre/user-management/index.md#user-account-management) names. To view user accounts parameters, see the system table [system.users](../../operations/system-tables/users.md#system_tables-users).
**Syntax**
``` sql
SHOW USERS
```
2021-07-29 15:20:55 +00:00
2022-06-02 10:55:18 +00:00
## SHOW ROLES
2023-03-18 02:45:43 +00:00
Returns a list of [roles](../../guides/sre/user-management/index.md#role-management). To view another parameters, see system tables [system.roles](../../operations/system-tables/roles.md#system_tables-roles) and [system.role_grants](../../operations/system-tables/role-grants.md#system_tables-role_grants).
**Syntax**
``` sql
SHOW [CURRENT|ENABLED] ROLES
```
2022-06-02 10:55:18 +00:00
## SHOW PROFILES
2023-03-18 02:45:43 +00:00
Returns a list of [setting profiles](../../guides/sre/user-management/index.md#settings-profiles-management). To view user accounts parameters, see the system table [settings_profiles](../../operations/system-tables/settings_profiles.md#system_tables-settings_profiles).
**Syntax**
``` sql
SHOW [SETTINGS] PROFILES
```
2022-06-02 10:55:18 +00:00
## SHOW POLICIES
2023-03-18 02:45:43 +00:00
Returns a list of [row policies](../../guides/sre/user-management/index.md#row-policy-management) for the specified table. To view user accounts parameters, see the system table [system.row_policies](../../operations/system-tables/row_policies.md#system_tables-row_policies).
**Syntax**
``` sql
SHOW [ROW] POLICIES [ON [db.]table]
```
2022-06-02 10:55:18 +00:00
## SHOW QUOTAS
2023-03-18 02:45:43 +00:00
Returns a list of [quotas](../../guides/sre/user-management/index.md#quotas-management). To view quotas parameters, see the system table [system.quotas](../../operations/system-tables/quotas.md#system_tables-quotas).
**Syntax**
``` sql
SHOW QUOTAS
2021-07-29 15:27:50 +00:00
```
2022-06-02 10:55:18 +00:00
## SHOW QUOTA
Returns a [quota](../../operations/quotas.md) consumption for all users or for current user. To view another parameters, see system tables [system.quotas_usage](../../operations/system-tables/quotas_usage.md#system_tables-quotas_usage) and [system.quota_usage](../../operations/system-tables/quota_usage.md#system_tables-quota_usage).
**Syntax**
``` sql
SHOW [CURRENT] QUOTA
```
2022-06-02 10:55:18 +00:00
## SHOW ACCESS
2023-03-18 02:45:43 +00:00
Shows all [users](../../guides/sre/user-management/index.md#user-account-management), [roles](../../guides/sre/user-management/index.md#role-management), [profiles](../../guides/sre/user-management/index.md#settings-profiles-management), etc. and all their [grants](../../sql-reference/statements/grant.md#grant-privileges).
**Syntax**
``` sql
SHOW ACCESS
```
2022-06-02 10:55:18 +00:00
## SHOW CLUSTER(s)
2020-12-27 21:45:07 +00:00
Returns a list of clusters. All available clusters are listed in the [system.clusters](../../operations/system-tables/clusters.md) table.
2022-09-20 11:00:10 +00:00
:::note
`SHOW CLUSTER name` query displays the contents of system.clusters table for this cluster.
:::
2021-01-17 13:24:58 +00:00
**Syntax**
2020-12-27 21:45:07 +00:00
``` sql
2021-01-19 17:45:56 +00:00
SHOW CLUSTER '<name>'
SHOW CLUSTERS [[NOT] LIKE|ILIKE '<pattern>'] [LIMIT <N>]
2020-12-27 21:45:07 +00:00
```
**Examples**
2020-12-27 21:45:07 +00:00
2021-01-17 13:24:58 +00:00
Query:
2020-12-27 21:45:07 +00:00
``` sql
SHOW CLUSTERS;
2021-01-17 13:24:58 +00:00
```
Result:
```text
┌─cluster──────────────────────────────────────┐
│ test_cluster_two_shards │
│ test_cluster_two_shards_internal_replication │
│ test_cluster_two_shards_localhost │
│ test_shard_localhost │
│ test_shard_localhost_secure │
│ test_unavailable_shard │
└──────────────────────────────────────────────┘
```
Query:
``` sql
SHOW CLUSTERS LIKE 'test%' LIMIT 1;
```
Result:
```text
┌─cluster─────────────────┐
│ test_cluster_two_shards │
└─────────────────────────┘
```
Query:
``` sql
SHOW CLUSTER 'test_shard_localhost' FORMAT Vertical;
```
Result:
```text
Row 1:
──────
cluster: test_shard_localhost
shard_num: 1
shard_weight: 1
replica_num: 1
host_name: localhost
host_address: 127.0.0.1
port: 9000
is_local: 1
user: default
default_database:
errors_count: 0
estimated_recovery_time: 0
2020-12-27 21:45:07 +00:00
```
2022-06-02 10:55:18 +00:00
## SHOW SETTINGS
2021-03-06 08:59:50 +00:00
Returns a list of system settings and their values. Selects data from the [system.settings](../../operations/system-tables/settings.md) table.
**Syntax**
```sql
2021-03-06 09:26:55 +00:00
SHOW [CHANGED] SETTINGS LIKE|ILIKE <name>
2021-03-06 08:59:50 +00:00
```
**Clauses**
2021-03-10 07:03:03 +00:00
`LIKE|ILIKE` allow to specify a matching pattern for the setting name. It can contain globs such as `%` or `_`. `LIKE` clause is case-sensitive, `ILIKE` — case insensitive.
2021-03-06 08:59:50 +00:00
When the `CHANGED` clause is used, the query returns only settings changed from their default values.
**Examples**
Query with the `LIKE` clause:
```sql
SHOW SETTINGS LIKE 'send_timeout';
```
Result:
```text
┌─name─────────┬─type────┬─value─┐
│ send_timeout │ Seconds │ 300 │
└──────────────┴─────────┴───────┘
```
Query with the `ILIKE` clause:
```sql
SHOW SETTINGS ILIKE '%CONNECT_timeout%'
```
Result:
```text
┌─name────────────────────────────────────┬─type─────────┬─value─┐
│ connect_timeout │ Seconds │ 10 │
│ connect_timeout_with_failover_ms │ Milliseconds │ 50 │
│ connect_timeout_with_failover_secure_ms │ Milliseconds │ 100 │
└─────────────────────────────────────────┴──────────────┴───────┘
```
Query with the `CHANGED` clause:
```sql
SHOW CHANGED SETTINGS ILIKE '%MEMORY%'
```
Result:
```text
┌─name─────────────┬─type───┬─value───────┐
│ max_memory_usage │ UInt64 │ 10000000000 │
└──────────────────┴────────┴─────────────┘
```
2022-09-20 11:00:10 +00:00
## SHOW FILESYSTEM CACHES
```sql
SHOW FILESYSTEM CACHES
```
Result:
``` text
┌─Caches────┐
│ s3_cache │
└───────────┘
```
2021-03-06 08:59:50 +00:00
**See Also**
- [system.settings](../../operations/system-tables/settings.md) table
2023-01-31 23:50:53 +00:00
## SHOW ENGINES
``` sql
SHOW ENGINES [INTO OUTFILE filename] [FORMAT format]
```
Outputs the content of the [system.table_engines](../../operations/system-tables/table_engines.md) table, that contains description of table engines supported by server and their feature support information.
**See Also**
- [system.table_engines](../../operations/system-tables/table_engines.md) table