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Inserting Data into ClickHouse

You can use the familiar INSERT INTO TABLE command with ClickHouse, but it is important to understand that each insert into a MergeTree table causes a part to be created in storage. Even for a simple example, let's insert more than one row at a time:

INSERT INTO helloworld.my_first_table (user_id, message, timestamp, metric) VALUES
    (101, 'Hello, ClickHouse!',                                 now(),       -1.0    ),
    (102, 'Insert a lot of rows per batch',                     yesterday(), 1.41421 ),
    (102, 'Sort your data based on your commonly-used queries', today(),     2.718   ),
    (101, 'Granules are the smallest chunks of data read',      now() + 5,   3.14159 )
  • Notice the timestamp column is populated using various Date and DateTime functions. ClickHouse has hundreds of useful functions that you can view in the Functions section.

Let's verify it worked - you should see the four rows of data that were inserted.

SELECT * FROM helloworld.my_first_table
tip

Insert a large number of rows per batch - tens of thousands or even millions of rows at once. Don't worry - ClickHouse can easily handle that type of volume!

tip

If you can not insert a lot of rows at once and you are using an HTTP client, use the async_insert setting, which batches your smaller inserts before inserting them into the table.

Integrating with ClickHouse​

No matter where your data sits, there is likely a table function, table engine, or other type of tool available to insert your data into ClickHouse. Check out our Integrations page for more details.