https://github.com/patricktrainer/dbt-no-select-star
Prevent `SELECT * FROM your_table;`
https://github.com/patricktrainer/dbt-no-select-star
dbt dbt-packages jinja2 macros sql
Last synced: 3 months ago
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Prevent `SELECT * FROM your_table;`
- Host: GitHub
- URL: https://github.com/patricktrainer/dbt-no-select-star
- Owner: patricktrainer
- License: apache-2.0
- Created: 2022-11-04T15:49:02.000Z (over 3 years ago)
- Default Branch: main
- Last Pushed: 2022-11-04T17:18:37.000Z (over 3 years ago)
- Last Synced: 2025-09-16T15:55:58.585Z (9 months ago)
- Topics: dbt, dbt-packages, jinja2, macros, sql
- Homepage:
- Size: 73.2 KB
- Stars: 0
- Watchers: 1
- Forks: 0
- Open Issues: 1
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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README
# dbt-no-select-star
This [dbt](https://github.com/dbt-labs/dbt) package contains a macro that will throw an error if you attempt to use `select *` in your model. This macro effectively forces you to be explicit about the columns you want to select.
## Installation
Adding this package to your project will enable the macro. To install, add the following to your `packages.yml` file:
```yml
packages:
- git: "https://github.com/patricktrainer/dbt-no-select-star.git"
revision: 0.1.0
```
## Usage
To use the macro, simply add the following at the end of your model:
```sql
{{ no_select_star() }}
```
For example:
```sql
select
my_column,
my_other_column,
{{ no_select_star() }}
from {{ ref(my_table) }}
```
This will throw an error if you attempt to use `select *` in your model.
The error message will look like this:
```bash
'DONT SELECT * FROM THIS TABLE!!!1'
```
To avoid the error, be explicit about the columns you want to select:
```sql
select
my_column,
my_other_column
from {{ ref(my_table) }}
```
## How does this work?
This works by leveraging _computed columns_. Computed columns are a feature that allow you to create a column that is the result of a SQL expression. If you inspect [the macro](macros/no_select_star.sql), you'll notice that it creates a `string` typed column. This column is then cast as a `char()` type with a length of 1 byte. Obviously, the string "DONT SELECT * FROM THIS TABLE!!!1" is longer than 1 byte, so the cast will fail. This will cause the query to fail, and the error message will be displayed.