# 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                |

The Chalk SQL function reference documents the scalar
functions available in Chalk SQL expressions. For the complete inventory,
including aggregate and table-valued functions, query
"chalk.information_schema.functions", whose is_aggregate and
is_table_valued columns say which kind each name is.

### 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.
- Supported syntax. Each statement page documents the syntax and
restrictions that Chalk SQL supports. For expression syntax, such as
literals, struct and list access, CASE, and casts, see
Expressions. For named functions, see the
Chalk SQL function reference.
- 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.