![SQLFluff](https://raw.githubusercontent.com/sqlfluff/sqlfluff/main/images/sqlfluff-wide.png)

# The SQL Linter for Humans

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**SQLFluff** is a dialect-flexible and configurable SQL linter. Designed
with ELT applications in mind, **SQLFluff** also works with Jinja templating
and dbt. **SQLFluff** will auto-fix most linting errors, allowing you to focus
your time on what matters.

## Table of Contents

1. [Dialects Supported](#dialects-supported)
2. [Templates Supported](#templates-supported)
3. [VS Code Extension](#vs-code-extension)
4. [Getting Started](#getting-started)
5. [Documentation](#documentation)
6. [Releases](#releases)
7. [SQLFluff on Slack](#sqlfluff-on-slack)
8. [SQLFluff on Twitter](#sqlfluff-on-twitter)
9. [Contributing](#contributing)
10. [Sponsors](#sponsors)

## Dialects Supported

Although SQL is reasonably consistent in its implementations, there are several
different dialects available with variations of syntax and grammar. **SQLFluff**
currently supports the following SQL dialects (though perhaps not in full):

- ANSI SQL - this is the base version and on occasion may not strictly follow
  the ANSI/ISO SQL definition
- [Athena](https://aws.amazon.com/athena/)
- [BigQuery](https://cloud.google.com/bigquery/)
- [ClickHouse](https://clickhouse.com/)
- [Databricks](https://databricks.com/) (note: this extends the `sparksql` dialect with
  [Unity Catalog](https://docs.databricks.com/data-governance/unity-catalog/index.html) syntax).
- [Db2](https://www.ibm.com/analytics/db2)
- [DuckDB](https://duckdb.org/)
- [Exasol](https://www.exasol.com/)
- [Greenplum](https://greenplum.org/)
- [Hive](https://hive.apache.org/)
- [Impala](https://impala.apache.org/)
- [Materialize](https://materialize.com/)
- [MySQL](https://www.mysql.com/)
- [Oracle](https://docs.oracle.com/en/database/oracle/oracle-database/21/sqlrf/index.html)
- [PostgreSQL](https://www.postgresql.org/) (aka Postgres)
- [Redshift](https://docs.aws.amazon.com/redshift/index.html)
- [Snowflake](https://www.snowflake.com/)
- [SOQL](https://developer.salesforce.com/docs/atlas.en-us.soql_sosl.meta/soql_sosl/sforce_api_calls_soql.htm)
- [SparkSQL](https://spark.apache.org/docs/latest/)
- [SQLite](https://www.sqlite.org/)
- [StarRocks](https://www.starrocks.io)
- [Teradata](https://www.teradata.com/)
- [Transact-SQL](https://docs.microsoft.com/en-us/sql/t-sql/language-reference) (aka T-SQL)
- [Trino](https://trino.io/)
- [Vertica](https://www.vertica.com/)

We aim to make it easy to expand on the support of these dialects and also
add other, currently unsupported, dialects. Please [raise issues](https://github.com/sqlfluff/sqlfluff/issues)
(or upvote any existing issues) to let us know of demand for missing support.

Pull requests from those that know the missing syntax or dialects are especially
welcomed and are the question way for you to get support added. We are happy
to work with any potential contributors on this to help them add this support.
Please raise an issue first for any large feature change to ensure it is a good
fit for this project before spending time on this work.

## Templates Supported

SQL itself does not lend itself well to [modularity](https://docs.getdbt.com/docs/viewpoint#section-modularity),
so to introduce some flexibility and reusability it is often [templated](https://en.wikipedia.org/wiki/Template_processor)
as discussed more in [our modularity documentation](https://docs.sqlfluff.com/en/stable/perma/modularity.html).

**SQLFluff** supports the following templates:

- [Jinja](https://jinja.palletsprojects.com/) (aka Jinja2)
- SQL placeholders (e.g. SQLAlchemy parameters)
- [Python format strings](https://docs.python.org/3/library/string.html#format-string-syntax)
- [dbt](https://www.getdbt.com/) (requires plugin)

Again, please raise issues if you wish to support more templating languages/syntaxes.

## VS Code Extension

We also have a VS Code extension:

- [Github Repository](https://github.com/sqlfluff/vscode-sqlfluff)
- [Extension in VS Code marketplace](https://marketplace.visualstudio.com/items?itemName=dorzey.vscode-sqlfluff)

# Getting Started

To get started, install the package and run `sqlfluff lint` or `sqlfluff fix`.

```shell
$ pip install sqlfluff
$ echo "  SELECT a  +  b FROM tbl;  " > test.sql
$ sqlfluff lint test.sql --dialect ansi
== [test.sql] FAIL
L:   1 | P:   1 | LT01 | Expected only single space before 'SELECT' keyword.
                       | Found '  '. [layout.spacing]
L:   1 | P:   1 | LT02 | First line should not be indented.
                       | [layout.indent]
L:   1 | P:   1 | LT13 | Files must not begin with newlines or whitespace.
                       | [layout.start_of_file]
L:   1 | P:  11 | LT01 | Expected only single space before binary operator '+'.
                       | Found '  '. [layout.spacing]
L:   1 | P:  14 | LT01 | Expected only single space before naked identifier.
                       | Found '  '. [layout.spacing]
L:   1 | P:  27 | LT01 | Unnecessary trailing whitespace at end of file.
                       | [layout.spacing]
L:   1 | P:  27 | LT12 | Files must end with a single trailing newline.
                       | [layout.end_of_file]
All Finished 📜 🎉!
```

Alternatively, you can use the [**Official SQLFluff Docker Image**](https://hub.docker.com/r/sqlfluff/sqlfluff)
or have a play using [**SQLFluff online**](https://online.sqlfluff.com/).

For full [CLI usage](https://docs.sqlfluff.com/en/stable/perma/cli.html) and
[rules reference](https://docs.sqlfluff.com/en/stable/perma/rules.html), see
[the SQLFluff docs](https://docs.sqlfluff.com/en/stable/).

# Documentation

For full documentation visit [docs.sqlfluff.com](https://docs.sqlfluff.com/en/stable/).
This documentation is generated from this repository so please raise
[issues](https://github.com/sqlfluff/sqlfluff/issues) or pull requests
for any additions, corrections, or clarifications.

# Releases

**SQLFluff** adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html),
so breaking changes should be restricted to major versions releases. Some
elements (such as the python API) are in a less stable state and may see more
significant changes more often. For details on breaking changes and how
to migrate between versions, see our
[release notes](https://docs.sqlfluff.com/en/latest/perma/releasenotes.html). See the
[changelog](CHANGELOG.md) for more details. If you would like to join in, please
consider [contributing](CONTRIBUTING.md).

New releases are made monthly. For more information, visit
[Releases](https://github.com/sqlfluff/sqlfluff/releases).

# SQLFluff on Slack

We have a fast-growing community
[on Slack](https://join.slack.com/t/sqlfluff/shared_invite/zt-2qtu36kdt-OS4iONPbQ3aCz2DIbYJdWg),
come and join us!

# SQLFluff on Twitter

Follow us [on Twitter @SQLFluff](https://twitter.com/SQLFluff) for announcements
and other related posts.

# Contributing

We are grateful to all our [contributors](https://github.com/sqlfluff/sqlfluff/graphs/contributors).
There is a lot to do in this project, and we are just getting started.

If you want to understand more about the architecture of **SQLFluff**, you can
find [more here](https://docs.sqlfluff.com/en/latest/perma/architecture.html).

If you would like to contribute, check out the
[open issues on GitHub](https://github.com/sqlfluff/sqlfluff/issues). You can also see
the guide to [contributing](CONTRIBUTING.md).

# Sponsors

<img src="images/datacoves.png" alt="Datacoves" width="150"/><br>
The turnkey analytics stack, find out more at [Datacoves.com](https://datacoves.com/).
