ignore functions with more than one element ...

[fmms]

Brief summary of the change made

fixes #3583

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

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.

[codecov]

Codecov Report

Merging #3792 (6bab1b7) into main (1ed4d84) will not change coverage.
The diff coverage is 100.00%.

@@            Coverage Diff            @@
##              main     #3792   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files          179       179           
  Lines        13727     13729    +2     
=========================================
+ Hits         13727     13729    +2     

Impacted Files	Coverage Δ
src/sqlfluff/rules/L010.py	100.00% <100.00%> (ø)

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[tunetheweb]

I found this difficult to follow. Would it be easier to just say something like this:

Suggested change

	# If the parent element is a function_name and there is more than one element
	# below it, we ignore it because it is most likely a user defined function.
	# SUM() should be modified. However, dbo.myScalar() must not be modified.
	# Used by L030 (that inherits from this rule)
	# If it's a qualified function_name (i.e with more than one part to
	# function_name). Then it is likely an existing user defined function (UDF)
	# which are case sensitive so ignore for this.

I wonder should there be a include_qualified_functions option in this (defaulted to false)?

Also, I think in some SQL dialects there might be a SYS schema or such like that contains the system functions, which are case insensitive? Then again not sure if there's a good reason to use that, so maybe fine to ignore that edge case.

[barrywhart]

@tunetheweb: Could you take another look at this since you'd requested changes on it?