SET Statement

SET param = value

Assigns value to the param setting for the current session. You cannot change server settings this way.

You can also set all the values from the specified settings profile in a single query.

SET profile = 'profile-name-from-the-settings-file'

For boolean settings set to true, you can use a shorthand syntax by omitting the value assignment. When only the setting name is specified, it is automatically set to 1 (true).

-- These are equivalent:
SET force_index_by_date = 1
SET force_index_by_date

Setting query parameters

The SET statement can also be used to define query parameters by prefixing the parameter name with param_. Query parameters allow you to write generic queries with placeholders that are replaced with actual values at execution time.

SET param_name = value

To use a query parameter in your query, reference it with the syntax {name: datatype}:

SET param_id = 42;
SET param_name = 'John';

SELECT * FROM users
WHERE id = {id: UInt32}
AND name = {name: String};

Query parameters are particularly useful when the same query needs to be executed multiple times with different values.

For more detailed information about query parameters, including usage with the Identifier type, see Defining and Using Query Parameters.

For more information, see Settings.