Trino CLI

You can use Trino shell to query your Iceberg tables directly. This is useful when you want to inspect the data in your Iceberg tables for debugging or ad hoc queries.

How to Enter into Trino Shell

In your console, run the following to enter into Trino shell:

When you see trino>, you’re in.

Trino Catalog/Schema

The top level of Trino is the catalog. A catalog is a connector to a data source. For example, the iceberg catalog is a connector to the Iceberg tables in your project. This is like a database in Postgres.

Inside a catalog, there are schemas. A schema is a namespace for tables - it’s useful for grouping a bunch of tables. For example, the raw schema might contain the orders table and the project_staging schema might contain stg_iceberg__orders table. This is like a schema in Postgres.

Finally inside a schema, there are tables.

If you’d like to see a comparison of how Trino catalog/schema structure maps to other database systems, take a look at Database/Schema Terminologies docs.

Now, let’s list all the Trino catalogs (connectors) you have inside Trino shell:

You should see the iceberg catalog.

 Catalog 
---------
 iceberg 
 system  
(2 rows)

You can also check all the available schemas inside the iceberg catalog.

Let’s query the number of rows in the table stg_iceberg__orders in the schema project_staging in the catalog iceberg. Run the following:

You’ll see the output:

 _col0  
---------
 1000000 
(1 row)

It’s cumbersome to have to type the catalog and schema name every time you want to query a table. You can set the default catalog and schema so you don’t have to type them every time.

Instead of trino> you’ll see trino:raw> on the terminal. Now you can view all the tables in this schema by running:

You can also run any query you’d like in that schema:

And you should see the output:

 _col0  
---------
 1000000 
(1 row)