ClickHouse Client
ClickHouse provides a native command-line client for executing SQL queries directly against a ClickHouse server. It supports both interactive mode (for live query execution) and batch mode (for scripting and automation). Query results can be displayed in the terminal or exported to a file, with support for all ClickHouse output formats, such as Pretty, CSV, JSON, and more.
The client provides real-time feedback on query execution with a progress bar and the number of rows read, bytes processed and query execution time. It supports both command-line options and configuration files.
Install
To download ClickHouse, run:
To also install it, run:
See Install ClickHouse for more installation options.
Different client and server versions are compatible with one another, but some features may not be available in older clients. We recommend using the same version for client and server.
Run
If you only downloaded but did not install ClickHouse, use ./clickhouse client instead of clickhouse-client.
To connect to a ClickHouse server, run:
Specify additional connection details as necessary:
| Option | Description |
|---|---|
--port <port> | The port ClickHouse server is accepting connections on. The default ports are 9440 (TLS) and 9000 (no TLS). Note that ClickHouse Client uses the native protocol and not HTTP(S). |
-s [ --secure ] | Whether to use TLS (usually autodetected). |
-u [ --user ] <username> | The database user to connect as. Connects as the default user by default. |
--password <password> | The password of the database user. You can also specify the password for a connection in the configuration file. If you do not specify the password, the client will ask for it. |
-c [ --config ] <path-to-file> | The location of the configuration file for ClickHouse Client, if it is not at one of the default locations. See Configuration Files. |
--connection <name> | The name of preconfigured connection details from the configuration file. |
For a complete list of command-line options, see Command Line Options.
Connecting to ClickHouse Cloud
The details for your ClickHouse Cloud service are available in the ClickHouse Cloud console. Select the service that you want to connect to and click Connect:
Choose Native, and the details are shown with an example clickhouse-client command:
Storing connections in a configuration file
You can store connection details for one or more ClickHouse servers in a configuration file.
The format looks like this:
See the section on configuration files for more information.
To concentrate on the query syntax, the rest of the examples leave off the connection details (--host, --port, etc.). Remember to add them when you use the commands.
Interactive mode
Using interactive mode
To run ClickHouse in interactive mode, simply execute:
This opens the Read-Eval-Print Loop (REPL) where you can start typing SQL queries interactively. Once connected, you'll get a prompt where you can enter queries:
In interactive mode, the default output format is PrettyCompact.
You can change the format in the FORMAT clause of the query or by specifying the --format command-line option.
To use the Vertical format, you can use --vertical or specify \G at the end of the query.
In this format, each value is printed on a separate line, which is convenient for wide tables.
In interactive mode, by default whatever was entered is run when you press Enter.
A semicolon is not necessary at the end of the query.
You can start the client with the -m, --multiline parameter.
To enter a multiline query, enter a backslash \ before the line feed.
After you press Enter, you will be asked to enter the next line of the query.
To run the query, end it with a semicolon and press Enter.
ClickHouse Client is based on replxx (similar to readline) so it uses familiar keyboard shortcuts and keeps a history.
The history is written to ~/.clickhouse-client-history by default.
To exit the client, press Ctrl+D, or enter one of the following instead of a query:
exitorexit;quitorquit;q,Qor:qlogoutorlogout;
Query processing information
When processing a query, the client shows:
- Progress, which is updated no more than 10 times per second by default. For quick queries, the progress might not have time to be displayed.
- The formatted query after parsing, for debugging.
- The result in the specified format.
- The number of lines in the result, the time passed, and the average speed of query processing. All data amounts refer to uncompressed data.
You can cancel a long query by pressing Ctrl+C.
However, you will still need to wait for a little for the server to abort the request.
It is not possible to cancel a query at certain stages.
If you do not wait and press Ctrl+C a second time, the client will exit.
ClickHouse Client allows passing external data (external temporary tables) for querying. For more information, see the section External data for query processing.
Aliases
You can use the following aliases from within the REPL:
\l- SHOW DATABASES\d- SHOW TABLES\c <DATABASE>- USE DATABASE.- repeat the last query
Keyboard shortcuts
Alt (Option) + Shift + e- open editor with the current query. It is possible to specify the editor to use with the environment variableEDITOR. By default,vimis used.Alt (Option) + #- comment line.Ctrl + r- fuzzy history search.
The full list with all available keyboard shortcuts is available at replxx.
To configure the correct work of the meta key (Option) on MacOS:
iTerm2: Go to Preferences -> Profile -> Keys -> Left Option key and click Esc+
Batch mode
Using batch mode
Instead of using ClickHouse Client interactively, you can run it in batch mode. In batch mode, ClickHouse executes a single query and exits immediately - there's no interactive prompt or loop.
You can specify a single query like this:
You can also use the --query command-line option:
You can provide a query on stdin:
Assuming the existence of a table messages, you can also insert data from the command line:
When --query is specified, any input is appended to the request after a line feed.
Inserting a CSV file into a remote ClickHouse service
This example is inserting a sample dataset CSV file, cell_towers.csv into an existing table cell_towers in the default database:
Examples of inserting data from the command line
There are several ways to insert data from the command line. The example below inserts two rows of CSV data into a ClickHouse table using batch mode:
In the example below cat <<_EOF starts a heredoc that will read everything until it sees _EOF again, then outputs it:
In the example below, the contents of file.csv are output to stdout using cat, and piped into clickhouse-client as input:
In batch mode, the default data format is TabSeparated.
You can set the format in the FORMAT clause of the query as shown in the example above.
Queries with parameters
You can specify parameters in a query and pass values to it with command-line options. This avoids formatting a query with specific dynamic values on the client side. For example:
It is also possible to set parameters from within an interactive session:
Query syntax
In the query, place the values that you want to fill using command-line parameters in braces in the following format:
| Parameter | Description |
|---|---|
name | Placeholder identifier. The corresponding command-line option is --param_<name> = value. |
data type | Data type of the parameter. For example, a data structure like (integer, ('string', integer)) can have the Tuple(UInt8, Tuple(String, UInt8)) data type (you can also use other integer types). It is also possible to pass the table name, database name, and column names as parameters, in that case you would need to use Identifier as the data type. |
Examples
AI-powered SQL generation
ClickHouse Client includes built-in AI assistance for generating SQL queries from natural language descriptions. This feature helps users write complex queries without deep SQL knowledge.
The AI assistance works out of the box if you have either OPENAI_API_KEY or ANTHROPIC_API_KEY environment variable set. For more advanced configuration, see the Configuration section.
Usage
To use AI SQL generation, prefix your natural language query with ??:
The AI will:
- Explore your database schema automatically
- Generate appropriate SQL based on the discovered tables and columns
- Execute the generated query immediately
Example
Configuration
AI SQL generation requires configuring an AI provider in your ClickHouse Client configuration file. You can use either OpenAI, Anthropic, or any OpenAI-compatible API service.
Environment-based fallback
If no AI configuration is specified in the config file, ClickHouse Client will automatically try to use environment variables:
- First checks for
OPENAI_API_KEYenvironment variable - If not found, checks for
ANTHROPIC_API_KEYenvironment variable - If neither is found, AI features will be disabled
This allows quick setup without configuration files:
Configuration file
For more control over AI settings, configure them in your ClickHouse Client configuration file located at:
~/.clickhouse-client/config.xml(XML format)~/.clickhouse-client/config.yaml(YAML format)- Or specify a custom location with
--config-file
- XML
- YAML
Using OpenAI-compatible APIs (e.g., OpenRouter):
Minimal configuration examples:
Parameters
Required parameters
api_key- Your API key for the AI service. Can be omitted if set via environment variable:- OpenAI:
OPENAI_API_KEY - Anthropic:
ANTHROPIC_API_KEY - Note: API key in config file takes precedence over environment variable
- OpenAI:
provider- The AI provider:openaioranthropic- If omitted, uses automatic fallback based on available environment variables
Model configuration
model- The model to use (default: provider-specific)- OpenAI:
gpt-4o,gpt-4,gpt-3.5-turbo, etc. - Anthropic:
claude-3-5-sonnet-20241022,claude-3-opus-20240229, etc. - OpenRouter: Use their model naming like
anthropic/claude-3.5-sonnet
- OpenAI:
Connection settings
base_url- Custom API endpoint for OpenAI-compatible services (optional)timeout_seconds- Request timeout in seconds (default:30)
Schema exploration
enable_schema_access- Allow AI to explore database schemas (default:true)max_steps- Maximum tool-calling steps for schema exploration (default:10)
Generation parameters
temperature- Controls randomness, 0.0 = deterministic, 1.0 = creative (default:0.0)max_tokens- Maximum response length in tokens (default:1000)system_prompt- Custom instructions for the AI (optional)
How it works
The AI SQL generator uses a multi-step process:
Schema Discovery
The AI uses built-in tools to explore your database
- Lists available databases
- Discovers tables within relevant databases
- Examines table structures via
CREATE TABLEstatements
Query Generation
Based on the discovered schema, the AI generates SQL that:
- Matches your natural language intent
- Uses correct table and column names
- Applies appropriate joins and aggregations
Execution
The generated SQL is automatically executed and results are displayed
Limitations
- Requires an active internet connection
- API usage is subject to rate limits and costs from the AI provider
- Complex queries may require multiple refinements
- The AI has read-only access to schema information, not actual data
Security
- API keys are never sent to ClickHouse servers
- The AI only sees schema information (table/column names and types), not actual data
- All generated queries respect your existing database permissions
Connection string
Usage
ClickHouse Client alternatively supports connecting to a ClickHouse server using a connection string similar to MongoDB, PostgreSQL, MySQL. It has the following syntax:
| Component (all optional) | Description | Default |
|---|---|---|
user | Database username. | default |
password | Database user password. If : is specified and the password is blank, the client will prompt for the user's password. | - |
hosts_and_ports | List of hosts and optional ports host[:port] [, host:[port]], .... | localhost:9000 |
database | Database name. | default |
query_parameters | List of key-value pairs param1=value1[,¶m2=value2], .... For some parameters, no value is required. Parameter names and values are case-sensitive. | - |
Notes
If the username, password or database was specified in the connection string, it cannot be specified using --user, --password or --database (and vice versa).
The host component can either be a hostname or an IPv4 or IPv6 address. IPv6 addresses should be in square brackets:
Connection strings can contain multiple hosts. ClickHouse Client will try to connect to these hosts in order (from left to right). After the connection is established, no attempt to connect to the remaining hosts is made.
The connection string must be specified as the first argument of clickHouse-client.
The connection string can be combined with an arbitrary number of other command-line options except --host and --port.
The following keys are allowed for query_parameters:
| Key | Description |
|---|---|
secure (or s) | If specified, the client will connect to the server over a secure connection (TLS). See --secure in the command-line options. |
Percent encoding
Non-US ASCII, spaces and special characters in the following parameters must be percent-encoded:
userpasswordhostsdatabasequery parameters
Examples
Connect to localhost on port 9000 and execute the query SELECT 1.
Connect to localhost as user john with password secret, host 127.0.0.1 and port 9000
Connect to localhost as the default user, host with IPV6 address [::1] and port 9000.
Connect to localhost on port 9000 in multiline mode.
Connect to localhost using port 9000 as the user default.
Connect to localhost on port 9000 and default to the my_database database.
Connect to localhost on port 9000 and default to the my_database database specified in the connection string and a secure connection using the shorthanded s parameter.
Connect to the default host using the default port, the default user, and the default database.
Connect to the default host using the default port, as the user my_user and no password.
Connect to localhost using the email as the user name. @ symbol is percent encoded to %40.
Connect to one of two hosts: 192.168.1.15, 192.168.1.25.
Query ID format
In interactive mode ClickHouse Client shows the query ID for every query. By default, the ID is formatted like this:
A custom format may be specified in a configuration file inside a query_id_formats tag. The {query_id} placeholder in the format string is replaced with the query ID. Several format strings are allowed inside the tag.
This feature can be used to generate URLs to facilitate profiling of queries.
Example
With the configuration above, the ID of a query is shown in the following format:
Configuration files
ClickHouse Client uses the first existing file of the following:
- A file that is defined with the
-c [ -C, --config, --config-file ]parameter. ./clickhouse-client.[xml|yaml|yml]~/.clickhouse-client/config.[xml|yaml|yml]/etc/clickhouse-client/config.[xml|yaml|yml]
See the sample configuration file in the ClickHouse repository: clickhouse-client.xml
- XML
- YAML
Environment variable options
The user name, password and host can be set via environment variables CLICKHOUSE_USER, CLICKHOUSE_PASSWORD and CLICKHOUSE_HOST.
Command line arguments --user, --password or --host, or a connection string (if specified) take precedence over environment variables.
Command-line options
All command-line options can be specified directly on the command line or as defaults in the configuration file.
General options
| Option | Description | Default |
|---|---|---|
-c [ -C, --config, --config-file ] <path-to-file> | The location of the configuration file for the client, if it is not at one of the default locations. See Configuration Files. | - |
--help | Print usage summary and exit. Combine with --verbose to display all possible options including query settings. | - |
--history_file <path-to-file> | Path to a file containing the command history. | - |
--history_max_entries | Maximum number of entries in the history file. | 1000000 (1 million) |
--prompt <prompt> | Specify a custom prompt. | The display_name of the server |
--verbose | Increase output verbosity. | - |
-V [ --version ] | Print version and exit. | - |
Connection options
| Option | Description | Default |
|---|---|---|
--connection <name> | The name of preconfigured connection details from the configuration file. See Connection credentials. | - |
-d [ --database ] <database> | Select the database to default to for this connection. | The current database from the server settings (default by default) |
-h [ --host ] <host> | The hostname of the ClickHouse server to connect to. Can either be a hostname or an IPv4 or IPv6 address. Multiple hosts can be passed via multiple arguments. | localhost |
--jwt <value> | Use JSON Web Token (JWT) for authentication. Server JWT authorization is only available in ClickHouse Cloud. | - |
--no-warnings | Disable showing warnings from system.warnings when the client connects to the server. | - |
--password <password> | The password of the database user. You can also specify the password for a connection in the configuration file. If you do not specify the password, the client will ask for it. | - |
--port <port> | The port the server is accepting connections on. The default ports are 9440 (TLS) and 9000 (no TLS). Note: The client uses the native protocol and not HTTP(S). | 9440 if --secure is specified, 9000 otherwise. Always defaults to 9440 if the hostname ends in .clickhouse.cloud. |
-s [ --secure ] | Whether to use TLS. Enabled automatically when connecting to port 9440 (the default secure port) or ClickHouse Cloud. You might need to configure your CA certificates in the configuration file. The available configuration settings are the same as for server-side TLS configuration. | Auto-enabled when connecting to port 9440 or ClickHouse Cloud |
--ssh-key-file <path-to-file> | File containing the SSH private key for authenticate with the server. | - |
--ssh-key-passphrase <value> | Passphrase for the SSH private key specified in --ssh-key-file. | - |
-u [ --user ] <username> | The database user to connect as. | default |
Instead of the --host, --port, --user and --password options, the client also supports connection strings.
Query options
| Option | Description |
|---|---|
--param_<name>=<value> | Substitution value for a parameter of a query with parameters. |
-q [ --query ] <query> | The query to run in batch mode. Can be specified multiple times (--query "SELECT 1" --query "SELECT 2") or once with multiple semicolon-separated queries (--query "SELECT 1; SELECT 2;"). In the latter case, INSERT queries with formats other than VALUES must be separated by empty lines. A single query can also be specified without a parameter: clickhouse-client "SELECT 1" Cannot be used together with --queries-file. |
--queries-file <path-to-file> | Path to a file containing queries. --queries-file can be specified multiple times, e.g. --queries-file queries1.sql --queries-file queries2.sql. Cannot be used together with --query. |
-m [ --multiline ] | If specified, allow multiline queries (do not send the query on Enter). Queries will be sent only when they are ended with a semicolon. |
Query settings
Query settings can be specified as command-line options in the client, for example:
See Settings for a list of settings.
Formatting options
| Option | Description | Default |
|---|---|---|
-f [ --format ] <format> | Use the specified format to output the result. See Formats for Input and Output Data for a list of supported formats. | TabSeparated |
--pager <command> | Pipe all output into this command. Typically less (e.g., less -S to display wide result sets) or similar. | - |
-E [ --vertical ] | Use the Vertical format to output the result. This is the same as –-format Vertical. In this format, each value is printed on a separate line, which is helpful when displaying wide tables. | - |
Execution details
| Option | Description | Default |
|---|---|---|
--enable-progress-table-toggle | Enable toggling of the progress table by pressing the control key (Space). Only applicable in interactive mode with progress table printing enabled. | enabled |
--hardware-utilization | Print hardware utilization information in progress bar. | - |
--memory-usage | If specified, print memory usage to stderr in non-interactive mode. Possible values: • none - do not print memory usage • default - print number of bytes • readable - print memory usage in human-readable format | - |
--print-profile-events | Print ProfileEvents packets. | - |
--progress | Print progress of query execution. Possible values: • tty|on|1|true|yes - outputs to the terminal in interactive mode • err - outputs to stderr in non-interactive mode • off|0|false|no - disables progress printing | tty in interactive mode, off in non-interactive (batch) mode |
--progress-table | Print a progress table with changing metrics during query execution. Possible values: • tty|on|1|true|yes - outputs to the terminal in interactive mode • err - outputs to stderr non-interactive mode • off|0|false|no - disables the progress table | tty in interactive mode, off in non-interactive (batch) mode |
--stacktrace | Print stack traces of exceptions. | - |
-t [ --time ] | Print query execution time to stderr in non-interactive mode (for benchmarks). | - |