ClickHouse/docs/en/operations/startup-scripts.md

slug	sidebar_label
/en/operations/startup-scripts	Startup Scripts

Startup Scripts

ClickHouse can run arbitrary SQL queries from the server configuration during startup. This can be useful for migrations or automatic schema creation.

<clickhouse>
    <startup_scripts>
        <scripts>
            <query>CREATE ROLE OR REPLACE test_role</query>
        </scripts>
        <scripts>
            <query>CREATE TABLE TestTable (id UInt64) ENGINE=TinyLog</query>
            <condition>SELECT 1;</condition>
        </scripts>
    </startup_scripts>
</clickhouse>

ClickHouse executes all queries from the startup_scripts sequentially in the specified order. If any of the queries fail, the execution of the following queries won't be interrupted.

You can specify a conditional query in the config. In that case, the corresponding query executes only when the condition query returns the value 1 or true.

:::note If the condition query returns any other value than 1 or true, the result will be interpreted as false, and the corresponding won't be executed. :::