Snowflake: Complete DELETE FROM grammar

[jpy-git]

Brief summary of the change made

Following on from my work on the Postgres DELETE FROM grammar in #2791 I'm updating the Snowflake statement accordingly.
Fixes alias behavior for multiple table expressions.
Included comprehensive unit tests (verified on snowflake).

Are there any other side effects of this change that we should be aware of?

No

Pull Request checklist

• Please confirm you have completed any of the necessary steps below.

• Included test cases to demonstrate any code changes, which may be one or more of the following:

  • .yml rule test cases in test/fixtures/rules/std_rule_cases.
  • .sql/.yml parser test cases in test/fixtures/dialects (note YML files can be auto generated with tox -e generate-fixture-yml).
  • Full autofix test cases in test/fixtures/linter/autofix.
  • Other.

• Added appropriate documentation for the change.

• Created GitHub issues for any relevant followup/future enhancements if appropriate.

[tunetheweb]

There are a few rules test cases like this:

test_snowflake_delete_cte:
  fail_str: |
    DELETE FROM MYTABLE1
        USING (
            WITH MYCTE AS (SELECT COLUMN2 FROM MYTABLE3 AS MT3)
            SELECT COLUMN3 FROM MYTABLE3
        ) X
    WHERE COLUMN1 = X.COLUMN3
  fix_str: |
    DELETE FROM MYTABLE1
        USING (
            WITH MYCTE AS (SELECT COLUMN2 FROM MYTABLE3)
            SELECT COLUMN3 FROM MYTABLE3
        ) X
    WHERE COLUMN1 = X.COLUMN3
  configs:
    core:
      dialect: snowflake

But this no longer parses as it's missing the AS.

Is the test wrong? If so can you update it? If not can you make the AS optional again?

[jpy-git]

Good spot, I've tested and verified optional AS is fine. I've added the relevant unit tests 👍

[codecov]

Codecov Report

Merging #2792 (b7d39a1) into main (c19c5b2) will not change coverage.
The diff coverage is 100.00%.

@@            Coverage Diff            @@
##              main     #2792   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files          163       163           
  Lines        12297     12290    -7     
=========================================
- Hits         12297     12290    -7     

Impacted Files	Coverage Δ
src/sqlfluff/dialects/dialect_snowflake.py	100.00% <100.00%> (ø)

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update c19c5b2...b7d39a1. Read the comment docs.