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

169 lines
4.6 KiB
Markdown
Raw Blame History

This file contains ambiguous Unicode characters

This file contains Unicode characters that might be confused with other characters. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

---
slug: /zh/sql-reference/statements/show
sidebar_position: 38
sidebar_label: SHOW
---
# SHOW 查询 {#show-queries}
## SHOW CREATE TABLE {#show-create-table}
``` sql
SHOW CREATE [TEMPORARY] [TABLE|DICTIONARY] [db.]table [INTO OUTFILE filename] [FORMAT format]
```
返回单个字符串类型的 statement其中只包含了一个值 - 用来创建指定对象的 `CREATE` 语句。
注意,如果使用该查询去获取系统表的 `CREATE` 语句,你得到的是一个虚构的语句,仅用来展示系统的表结构,而不能实际创建表。
## SHOW DATABASES {#show-databases}
``` sql
SHOW DATABASES [INTO OUTFILE filename] [FORMAT format]
```
打印所有的数据库列表,该查询等同于 `SELECT name FROM system.databases [INTO OUTFILE filename] [FORMAT format]`
## SHOW PROCESSLIST {#show-processlist}
``` sql
SHOW PROCESSLIST [INTO OUTFILE filename] [FORMAT format]
```
输出 [system.processes](../../operations/system-tables/processes.md#system_tables-processes)表的内容,包含有当前正在处理的请求列表,除了 `SHOW PROCESSLIST`查询。
`SELECT * FROM system.processes` 查询返回和当前请求相关的所有数据
提示 (在控制台执行):
``` bash
$ watch -n1 "clickhouse-client --query='SHOW PROCESSLIST'"
```
## SHOW TABLES {#show-tables}
显示表的清单
``` sql
SHOW [TEMPORARY] TABLES [{FROM | IN} <db>] [LIKE '<pattern>' | WHERE expr] [LIMIT <N>] [INTO OUTFILE <filename>] [FORMAT <format>]
```
如果未使用 `FROM` 字句,该查询返回当前数据库的所有表清单
可以用下面的方式获得和 `SHOW TABLES`一样的结果:
``` sql
SELECT name FROM system.tables WHERE database = <db> [AND name LIKE <pattern>] [LIMIT <N>] [INTO OUTFILE <filename>] [FORMAT <format>]
```
**示例**
下列查询获取最前面的2个位于`system`库中且表名包含 `co`的表。
``` sql
SHOW TABLES FROM system LIKE '%co%' LIMIT 2
```
``` text
┌─name───────────────────────────┐
│ aggregate_function_combinators │
│ collations │
└────────────────────────────────┘
```
## SHOW DICTIONARIES {#show-dictionaries}
以列表形式显示 [外部字典](../../sql-reference/dictionaries/external-dictionaries/external-dicts.md).
``` sql
SHOW DICTIONARIES [FROM <db>] [LIKE '<pattern>'] [LIMIT <N>] [INTO OUTFILE <filename>] [FORMAT <format>]
```
如果 `FROM`字句没有指定,返回当前数据库的字典列表
可以通过下面的查询获取和 `SHOW DICTIONARIES`相同的结果:
``` sql
SELECT name FROM system.dictionaries WHERE database = <db> [AND name LIKE <pattern>] [LIMIT <N>] [INTO OUTFILE <filename>] [FORMAT <format>]
```
**示例**
下列查询获取最前面的2个位于 `system`库中且名称包含 `reg`的字典表。
``` sql
SHOW DICTIONARIES FROM db LIKE '%reg%' LIMIT 2
```
``` text
┌─name─────────┐
│ regions │
│ region_names │
└──────────────┘
```
## SHOW GRANTS {#show-grants-statement}
显示用户的权限
### 语法 {#show-grants-syntax}
``` sql
SHOW GRANTS [FOR user]
```
如果未指定用户,输出当前用户的权限
## SHOW CREATE USER {#show-create-user-statement}
显示 [user creation](../../sql-reference/statements/create.md#create-user-statement)用到的参数。
`SHOW CREATE USER` 不会输出用户的密码信息
### 语法 {#show-create-user-syntax}
``` sql
SHOW CREATE USER [name | CURRENT_USER]
```
## SHOW CREATE ROLE {#show-create-role-statement}
显示 [role creation](../../sql-reference/statements/create.md#create-role-statement) 中用到的参数。
### 语法 {#show-create-role-syntax}
``` sql
SHOW CREATE ROLE name
```
## SHOW CREATE ROW POLICY {#show-create-row-policy-statement}
显示 [row policy creation](../../sql-reference/statements/create.md#create-row-policy-statement)中用到的参数
### 语法 {#show-create-row-policy-syntax}
``` sql
SHOW CREATE [ROW] POLICY name ON [database.]table
```
## SHOW CREATE QUOTA {#show-create-quota-statement}
显示 [quota creation](../../sql-reference/statements/create.md#create-quota-statement)中用到的参数
### 语法 {#show-create-row-policy-syntax}
``` sql
SHOW CREATE QUOTA [name | CURRENT]
```
## SHOW CREATE SETTINGS PROFILE {#show-create-settings-profile-statement}
显示 [settings profile creation](../../sql-reference/statements/create.md#create-settings-profile-statement)中用到的参数
### 语法 {#show-create-row-policy-syntax}
``` sql
SHOW CREATE [SETTINGS] PROFILE name
```