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clickhouse-client

clickhouse-client​

ClickHouse provides a native command-line client: clickhouse-client. The client supports command-line options and configuration files. For more information, see Configuring.

Install it from the clickhouse-client package and run it with the command clickhouse-client.

$ clickhouse-client
ClickHouse client version 20.13.1.5273 (official build).
Connecting to localhost:9000 as user default.
Connected to ClickHouse server version 20.13.1 revision 54442.

:)

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 of the client as the server app. When you try to use a client of the older version, then the server, clickhouse-client displays the message:

ClickHouse client version is older than ClickHouse server.
It may lack support for new features.

Usage​

The client can be used in interactive and non-interactive (batch) mode.

Gather your connection details​

To connect to ClickHouse with native TCP you need this information:

  • The HOST and PORT: typically, the port is 9440 when using TLS, or 9000 when not using TLS.

  • The DATABASE NAME: out of the box there is a database named default, use the name of the database that you want to connect to.

  • The USERNAME and PASSWORD: out of the box the username is default. Use the username appropriate for your use case.

The details for your ClickHouse Cloud service are available in the ClickHouse Cloud console. Select the service that you will connect to and click Connect:

ClickHouse Cloud service connect button

Choose Native, and the details are available in an example clickhouse-client command.

ClickHouse Cloud Native TCP connection details

If you are using self-managed ClickHouse, the connection details are set by your ClickHouse administrator.

Interactive​

To connect to your ClickHouse Cloud service, or any ClickHouse server using TLS and passwords, interactively use --secure, port 9440, and provide your username and password:

clickhouse-client --host <HOSTNAME> \
                  --secure \
                  --port 9440 \
                  --user <USERNAME> \
                  --password <PASSWORD>

To connect to a self-managed ClickHouse server you will need the details for that server. Whether or not TLS is used, port numbers, and passwords are all configurable. Use the above example for ClickHouse Cloud as a starting point.

Batch​

To use batch mode, specify the ‘query’ parameter, or send data to ‘stdin’ (it verifies that ‘stdin’ is not a terminal), or both. Similar to the HTTP interface, when using the ‘query’ parameter and sending data to ‘stdin’, the request is a concatenation of the ‘query’ parameter, a line feed, and the data in ‘stdin’. This is convenient for large INSERT queries.

Examples of using the client to insert data:

Inserting a CSV file into a remote ClickHouse service​

This example is appropriate for ClickHouse Cloud, or any ClickHouse server using TLS and a password. In this example a sample dataset CSV file, cell_towers.csv is inserted into an existing table cell_towers in the default database:

clickhouse-client --host HOSTNAME.clickhouse.cloud \
  --secure \
  --port 9440 \
  --user default \
  --password PASSWORD \
  --query "INSERT INTO cell_towers FORMAT CSVWithNames" \
  < cell_towers.csv
note

To concentrate on the query syntax, the rest of the examples leave off the connection details (--host, --port, etc.). Add them in when you try the commands.

Three different ways of inserting data​

echo -ne "1, 'some text', '2016-08-14 00:00:00'\n2, 'some more text', '2016-08-14 00:00:01'" | \
  clickhouse-client --database=test --query="INSERT INTO test FORMAT CSV";
cat <<_EOF | clickhouse-client --database=test --query="INSERT INTO test FORMAT CSV";
3, 'some text', '2016-08-14 00:00:00'
4, 'some more text', '2016-08-14 00:00:01'
_EOF
cat file.csv | clickhouse-client --database=test --query="INSERT INTO test FORMAT CSV";

Notes​

In batch mode, the default data format is TabSeparated. You can set the format in the FORMAT clause of the query.

By default, you can only process a single query in batch mode. To make multiple queries from a “script,” use the --multiquery parameter. This works for all queries except INSERT. Query results are output consecutively without additional separators. Similarly, to process a large number of queries, you can run ‘clickhouse-client’ for each query. Note that it may take tens of milliseconds to launch the ‘clickhouse-client’ program.

In interactive mode, you get a command line where you can enter queries.

If ‘multiline’ is not specified (the default): To run the query, press Enter. The semicolon is not necessary at the end of the query. 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.

If multiline is specified: To run a query, end it with a semicolon and press Enter. If the semicolon was omitted at the end of the entered line, you will be asked to enter the next line of the query.

Only a single query is run, so everything after the semicolon is ignored.

You can specify \G instead of or after the semicolon. This indicates Vertical format. In this format, each value is printed on a separate line, which is convenient for wide tables. This unusual feature was added for compatibility with the MySQL CLI.

The command line is based on ‘replxx’ (similar to ‘readline’). In other words, it uses the familiar keyboard shortcuts and keeps a history. The history is written to ~/.clickhouse-client-history.

By default, the format used is PrettyCompact. You can change the format in the FORMAT clause of the query, or by specifying \G at the end of the query, using the --format or --vertical argument in the command line, or using the client configuration file.

To exit the client, press Ctrl+D, or enter one of the following instead of a query: “exit”, “quit”, “logout”, “exit;”, “quit;”, “logout;”, “q”, “Q”, “:q”

When processing a query, the client shows:

  1. 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.
  2. The formatted query after parsing, for debugging.
  3. The result in the specified format.
  4. 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.

The command-line client allows passing external data (external temporary tables) for querying. For more information, see the section “External data for query processing”.

Queries with Parameters​

You can create a query with parameters and pass values to them from client application. This allows to avoid formatting query with specific dynamic values on client side. For example:

$ clickhouse-client --param_parName="[1, 2]"  -q "SELECT * FROM table WHERE a = {parName:Array(UInt16)}"

It is also possible to set parameters from within an interactive session:

$ clickhouse-client -nq "
  SET param_parName='[1, 2]';
  SELECT {parName:Array(UInt16)}"

Query Syntax​

Format a query as usual, then place the values that you want to pass from the app parameters to the query in braces in the following format:

{<name>:<data type>}
  • name — Placeholder identifier. In the console client it should be used in app parameters as --param_<name> = value.
  • data type — Data type of the app parameter value. For example, a data structure like (integer, ('string', integer)) can have the Tuple(UInt8, Tuple(String, UInt8)) data type (you can also use another integer types). It's also possible to pass table, database, column names as a parameter, in that case you would need to use Identifier as a data type.

Example​

$ clickhouse-client --param_tuple_in_tuple="(10, ('dt', 10))" -q "SELECT * FROM table WHERE val = {tuple_in_tuple:Tuple(UInt8, Tuple(String, UInt8))}"
$ clickhouse-client --param_tbl="numbers" --param_db="system" --param_col="number" --query "SELECT {col:Identifier} FROM {db:Identifier}.{tbl:Identifier} LIMIT 10"

Configuring​

You can pass parameters to clickhouse-client (all parameters have a default value) using:

  • From the Command Line

    Command-line options override the default values and settings in configuration files.

  • Configuration files.

    Settings in the configuration files override the default values.

Command Line Options​

  • --host, -h – The server name, ‘localhost’ by default. You can use either the name or the IPv4 or IPv6 address.
  • --port – The port to connect to. Default value: 9000. Note that the HTTP interface and the native interface use different ports.
  • --user, -u – The username. Default value: default.
  • --password – The password. Default value: empty string.
  • --ask-password - Prompt the user to enter a password.
  • --query, -q – The query to process when using non-interactive mode. --query can be specified multiple times, e.g. --query "SELECT 1" --query "SELECT 2". Cannot be used simultaneously with --queries-file.
  • --queries-file – file path with queries to execute. --queries-file can be specified multiple times, e.g. --query queries1.sql --query queries2.sql. Cannot be used simultaneously with --query.
  • --multiquery, -n – If specified, multiple queries separated by semicolons can be listed after the --query option. For convenience, it is also possible to omit --query and pass the queries directly after --multiquery.
  • --multiline, -m – If specified, allow multiline queries (do not send the query on Enter).
  • --database, -d – Select the current default database. Default value: the current database from the server settings (‘default’ by default).
  • --format, -f – Use the specified default format to output the result.
  • --vertical, -E – If specified, use the Vertical format by default 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.
  • --time, -t – If specified, print the query execution time to ‘stderr’ in non-interactive mode.
  • --stacktrace – If specified, also print the stack trace if an exception occurs.
  • --config-file – The name of the configuration file.
  • --secure – If specified, will connect to server over secure connection (TLS). 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.
  • --history_file — Path to a file containing command history.
  • --param_<name> — Value for a query with parameters.
  • --hardware-utilization — Print hardware utilization information in progress bar.
  • --print-profile-events – Print ProfileEvents packets.
  • --profile-events-delay-ms – Delay between printing ProfileEvents packets (-1 - print only totals, 0 - print every single packet).

Instead of --host, --port, --user and --password options, ClickHouse client also supports connection strings (see next section).

Connection string​

clickhouse-client alternatively supports connecting to clickhouse server using a connection string similar to MongoDB, PostgreSQL, MySQL. It has the following syntax:

clickhouse:[//[user[:password]@][hosts_and_ports]][/database][?query_parameters]

Where

  • user - (optional) is a user name,
  • password - (optional) is a user password. If : is specified and the password is blank, the client will prompt for the user's password.
  • hosts_and_ports - (optional) is a list of hosts and optional ports host[:port] [, host:[port]], ...,
  • database - (optional) is the database name,
  • query_parameters - (optional) is a list of key-value pairs param1=value1[,&param2=value2], .... For some parameters, no value is required. Parameter names and values are case-sensitive.

If no user is specified, default user without password will be used. If no host is specified, the localhost will be used (localhost). If no port is specified is not specified, 9000 will be used as port. If no database is specified, the default database will be used.

If the user name, 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 an a host name and IP address. Put an IPv6 address in square brackets to specify it:

clickhouse://[2001:db8::1234]

URI allows multiple hosts to be connected to. Connection strings can contain multiple hosts. ClickHouse-client will try to connect to these hosts in order (i.e. 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 arbitrary other command-line-options except --host/-h and --port.

The following keys are allowed for component query_parameter:

  • secure or shorthanded s - no value. If specified, client will connect to the server over a secure connection (TLS). See secure in command-line-options

Percent encoding​

Non-US ASCII, spaces and special characters in the user, password, hosts, database and query parameters must be percent-encoded.

Examples​

Connect to localhost using port 9000 and execute the query SELECT 1.

clickhouse-client clickhouse://localhost:9000 --query "SELECT 1"

Connect to localhost using user john with password secret, host 127.0.0.1 and port 9000

clickhouse-client clickhouse://john:secret@127.0.0.1:9000

Connect to localhost using default user, host with IPV6 address [::1] and port 9000.

clickhouse-client clickhouse://[::1]:9000

Connect to localhost using port 9000 in multiline mode.

clickhouse-client clickhouse://localhost:9000 '-m'

Connect to localhost using port 9000 with the user default.

clickhouse-client clickhouse://default@localhost:9000

# equivalent to:
clickhouse-client clickhouse://localhost:9000 --user default

Connect to localhost using port 9000 to my_database database.

clickhouse-client clickhouse://localhost:9000/my_database

# equivalent to:
clickhouse-client clickhouse://localhost:9000 --database my_database

Connect to localhost using port 9000 to my_database database specified in the connection string and a secure connection using shorthanded 's' URI parameter.

clickhouse-client clickhouse://localhost/my_database?s

# equivalent to:
clickhouse-client clickhouse://localhost/my_database -s

Connect to default host using default port, default user, and default database.

clickhouse-client clickhouse:

Connect to the default host using the default port, using user my_user and no password.

clickhouse-client clickhouse://my_user@

# Using a blank password between : and @ means to asking user to enter the password before starting the connection.
clickhouse-client clickhouse://my_user:@

Connect to localhost using email as the user name. @ symbol is percent encoded to %40.

clickhouse-client clickhouse://some_user%40some_mail.com@localhost:9000

Connect to one of provides hosts: 192.168.1.15, 192.168.1.25.

clickhouse-client clickhouse://192.168.1.15,192.168.1.25

Configuration Files​

clickhouse-client uses the first existing file of the following:

  • Defined in the --config-file parameter.
  • ./clickhouse-client.xml, .yaml, .yml
  • ~/.clickhouse-client/config.xml, .yaml, .yml
  • /etc/clickhouse-client/config.xml, .yaml, .yml

Example of a config file:

<config>
    <user>username</user>
    <password>password</password>
    <secure>true</secure>
    <openSSL>
      <client>
        <caConfig>/etc/ssl/cert.pem</caConfig>
      </client>
    </openSSL>
</config>

Or the same config in a YAML format:

user: username
password: 'password'
secure: true
openSSL:
  client:
    caConfig: '/etc/ssl/cert.pem'

Query ID Format​

In interactive mode clickhouse-client shows query ID for every query. By default, the ID is formatted like this:

Query id: 927f137d-00f1-4175-8914-0dd066365e96

A custom format may be specified in a configuration file inside a query_id_formats tag. {query_id} placeholder in the format string is replaced with the ID of a query. Several format strings are allowed inside the tag. This feature can be used to generate URLs to facilitate profiling of queries.

Example

<config>
  <query_id_formats>
    <speedscope>http://speedscope-host/#profileURL=qp%3Fid%3D{query_id}</speedscope>
  </query_id_formats>
</config>

If the configuration above is applied, the ID of a query is shown in the following format:

speedscope:http://speedscope-host/#profileURL=qp%3Fid%3Dc8ecc783-e753-4b38-97f1-42cddfb98b7d