Enhance usability of star macro by only generating column aliases when prefix and/or suffix is specified

[nickperrott]

This is a:

• bug fix PR with no breaking changes — please ensure the base branch is master
• new functionality — please ensure the base branch is the latest dev/ branch
• a breaking change — please ensure the base branch is the latest dev/ branch

Description & motivation

The current implementation of the star macro always generates column aliases. This limits its usage to the specified situation select * from {{ref('my_model')}}, replacing star (*) with the star macro.

With the simple addition of a condition, I have modified the star macro so that a column alias will only be added if there is a prefix and/or a suffix specified. This makes the star macro useful in other situations such as in WHERE or GROUP BY predicates such as: select ... from {ref('my_model')}} where (*) not in (select ..., replacing star (*) with the star macro.

This should also be a non-breaking change, as if neither a prefix and/or suffix is specified, then the column name alias is the same as the actual column name.

Checklist

• I have verified that these changes work locally on the following warehouses (Note: it's okay if you do not have access to all warehouses, this helps us understand what has been covered)
  • BigQuery
  • Postgres
  • Redshift
  • Snowflake
• I followed guidelines to ensure that my changes will work on "non-core" adapters by:
  • dispatching any new macro(s) so non-core adapters can also use them (e.g. the star() source)
  • using the limit_zero() macro in place of the literal string: limit 0
  • using dbt_utils.type_* macros instead of explicit datatypes (e.g. dbt_utils.type_timestamp() instead of TIMESTAMP
• I have updated the README.md (if applicable)
• I have added tests & descriptions to my models (and macros if applicable)
• I have added an entry to CHANGELOG.md

[joellabes]

Thanks @nickperrott! I'd love to get this merged in.

Quoting myself from 469:

Could I prevail upon you to add an integration test to the star macro that incorporates a window function or something similar, so that we can ensure that this issue doesn't arise in the future?

[joellabes]

@nickperrott checking in - how's your availability to wrap this one up? Or would you rather I took it from here?

[nickperrott]

Hi Joel, Thanks for reaching out again. Sorry, I am super busy trying to get our startup's first customer live and therefore have no time to work on any non-critical-path issues. Maybe at some point in the future I will have time to be able to contribute some code/tests to DBT, but definitely not in the short/medium term. Regards, Nick.

…

On 16/02/2022, at 2:44 PM, Joel Labes ***@***.***> wrote: @nickperrott <https://github.com/nickperrott> checking in - how's your availability to wrap this one up? Or would you rather I took it from here? — Reply to this email directly, view it on GitHub <#468 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/ALBPIKDT4FXWUVCBY45WV53U3L6OFANCNFSM5KOUTSOA>. Triage notifications on the go with GitHub Mobile for iOS <https://apps.apple.com/app/apple-store/id1477376905?ct=notification-email&mt=8&pt=524675> or Android <https://play.google.com/store/apps/details?id=com.github.android&referrer=utm_campaign%3Dnotification-email%26utm_medium%3Demail%26utm_source%3Dgithub>. You are receiving this because you were mentioned.

[jelstongreen]

Hi @nickperrott , I have made a PR to your fork to add the necessary test to the macro for alias checking. If you can merge it in we should be good to go

[joellabes]

Thank you @nickperrott and @jelstongreen for your work on this! Josh, I took inspiration from your tests and re-implemented them directly so that we can get this merged in.

The base branch was changed.