# Chalk SQL Statements
source: https://docs.chalk.ai/docs/chalksql/statements/overview

## The SQL statements supported by Chalk SQL.

Chalk SQL supports a focused set of SQL statements built around reading and
introspecting data across your Chalk environment. Each page in this section
documents one statement in detail, including its clauses, restrictions, and
examples.

| Statement                                                 | Description                                                                  |
| --------------------------------------------------------- | ---------------------------------------------------------------------------- |
| [`SELECT`](/docs/chalksql/statements/select)              | Query data from data sources, the offline store, and the Chalk catalog       |
| [`DESCRIBE` / `SHOW`](/docs/chalksql/statements/describe) | Inspect the schema of a table or query, or list available tables             |
| [`EXPLAIN`](/docs/chalksql/statements/explain)            | Show the physical plan for a statement, optionally with execution statistics |
| [`COPY ... TO`](/docs/chalksql/statements/copy)           | Write the result of a query to Parquet, CSV, or Iceberg files                |

For the full list of scalar, aggregate, and table-valued functions available in
Chalk SQL expressions, see the Chalk SQL function reference.

### General rules

- One statement per query. Each Chalk SQL request executes exactly one
statement. Submitting multiple ;-separated statements returns an error.
- Read-only. Chalk SQL is a read-only interface over the Chalk catalog and
your configured data sources. The one statement that produces output outside
of the query response is COPY ... TO,
which exports query results to files without modifying any source.
- DuckDB-style grammar. Chalk SQL parses queries with a DuckDB-derived
grammar, so syntax generally follows DuckDB's SQL
dialect. Chalk SQL implements its
own compiler and execution engine, however, so not every DuckDB construct is
supported — each statement page lists what is.
- Fully qualify catalog tables. Tables in the Chalk catalog and in
configured data sources are referenced by a quoted, fully-qualified
"catalog.schema.table" name, for example
SELECT * FROM "chalk.online_store.keys". See
Referencing the Chalk Catalog.