[Bug] --empty flag generates SQL that conflicts with subquery aliases

[khaledh]

Is this a new bug in dbt-core?

• I believe this is a new bug in dbt-core
• I have searched the existing issues, and I could not find an existing issue for this bug

Current Behavior

Running dbt run --empty generates SQL with a built-in alias like this (introduced here):

(select * from {rendered} where false limit 0) _dbt_limit_subq

If the original SQL already contains an alias, this causes a syntax error, e.g. this model:

SELECT ...
FROM {{ source('my_source', 'my_table') }} AS my_alias
JOIN ...

generates:

...
FROM (select * from `my_project`.`my_schema`.`my_table` where false limit 0) _dbt_limit_subq AS my_alias
...

-- Syntax error: Expected ")" but got keyword AS at [...]

Expected Behavior

I expect the --empty flag to generate valid subquery SQL that can be aliased for use in other parts of the query.

Steps To Reproduce

1. Create a model that uses an aliased subquery (as shown above)
2. Run dbt run --empty on the model

Relevant log output

No response

Environment

- OS: macOS Sonoma 14.4.1
- Python: 3.11.1
- dbt: 1.8.0-b2

Which database adapter are you using with dbt?

bigquery

Additional Context

No response

[dbeatty10]

Thanks for trying this out and reporting this @khaledh !

Do you get the same error when you run this?

dbt show -s your-model --limit 0

Also, are you installing dbt-core and dbt-bigquery from PyPI or from source (like either main or another branch)?

If PyPI, could you share your full output of dbt --version so we can see the versions of both dbt-core and dbt-bigquery that you have installed?

[dbeatty10]

@khaledh This looks the same as dbt-labs/dbt-adapters#124, so I'm going to close this as a duplicate.

Do you want to join in on that issue and offer any unique perspectives or insights there?

[khaledh]

@dbeatty10 Thanks for pointing out that other issue. Yes, it's the same issue, so no need for this one. I'll subscribe to the other issue.