Fix CTE support in SQLWrapper by implementing intelligent schema prefixing

[sergiossm]

• Add _extract_cte_names() method to identify CTE names in SQL queries
• Add _add_schema_prefix_smart() method to intelligently prefix table names while preserving CTE names
• Update run_sql() method to use smart schema prefixing instead of naive string replacement
• Add comprehensive tests for CTE functionality including:
  • CTE name extraction
  • Schema prefixing with CTEs
  • Multiple CTEs handling
  • Already schema-qualified table handling
  • End-to-end integration tests

Fixes #19889

Description

Please include a summary of the change and which issue is fixed. Please also include relevant motivation and context. List any dependencies that are required for this change.

Fixes # (issue)

New Package?

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• Yes
• No

Version Bump?

Did I bump the version in the pyproject.toml file of the package I am updating? (Except for the llama-index-core package)

• Yes
• No

Type of Change

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• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

How Has This Been Tested?

Your pull-request will likely not be merged unless it is covered by some form of impactful unit testing.

• I added new unit tests to cover this change
• I believe this change is already covered by existing unit tests

Suggested Checklist:

• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have added Google Colab support for the newly added notebooks.
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• I ran uv run make format; uv run make lint to appease the lint gods

[AstraBert]

Hey there @sergiossm, I'll happily review your PR once the tests are passing (currently the ones you introduced are failing in CI) and linting/type checking are ok :)

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[github-actions]

This PR was closed because it has been stalled for 10 days with no activity.