fix(sql): handle backtick-quoted identifiers with base dialect

[rusackas]

SUMMARY

When using the "Other" database type (or unknown engines), SQL parsing would fail if the query contained backtick-quoted identifiers like SELECT * FROM database.6``.

Root Cause: The base sqlglot dialect (Dialects.DIALECT) doesn't support backtick-quoted identifiers, but some databases (particularly MySQL-compatible ones like the sqlalchemy-mongobi connector mentioned in the issue) use backticks for quoting table/column names.

Solution: This change adds a fallback mechanism in the _parse method: when parsing fails with the base dialect (or no dialect for unknown engines) and the SQL contains backticks, we retry parsing with the MySQL dialect which supports backticks natively.

The fallback only triggers when:

1. The initial parse fails
2. The dialect is the base dialect OR None (unknown engine)
3. The SQL contains backtick characters

If the MySQL dialect also fails to parse the SQL, the original error is raised to maintain proper error messaging.

BEFORE/AFTER SCREENSHOTS OR ANIMATED GIF

Before: Queries with backtick-quoted identifiers fail with:

sqlglot.errors.ParseError: Invalid expression / Unexpected token. Line 1, Col: 24.
SELECT * FROM database.`6` LIMIT 100

After: Queries parse successfully, allowing datasets to be created and SQL Lab queries to run.

TESTING INSTRUCTIONS

1. Create a database connection with the "Other" database type
2. Try to create a dataset using SQL with backtick-quoted table names:
   • SELECT * FROM database.6``
   • SELECT * FROM my_table``
   • SELECT col1, col2FROMschema.table``
3. Verify the queries parse successfully and datasets can be created
4. Run the unit tests: pytest tests/unit_tests/sql/parse_tests.py -k "backtick" -v

ADDITIONAL INFORMATION

• Has associated issue: Fixes Other database - error on parsing SQL script in Superset 4.1.1 #31853
• Required feature flags:
• Changes UI
• Includes DB Migration
• Introduces new feature or API
• Removes existing feature or API

🤖 Generated with Claude Code

[Copilot]

Pull request overview

This PR fixes SQL parsing failures for backtick-quoted identifiers when using the "Other" database type or engines with unknown dialects. The fix implements a fallback mechanism that retries parsing with MySQL dialect when the base dialect fails and backticks are detected in the SQL.

Key changes:

• Added backtick fallback logic in SQLStatement._parse() method
• Comprehensive test coverage for various backtick-quoted identifier scenarios
• Maintains backward compatibility with normal SQL parsing

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
superset/sql/parse.py	Implements MySQL dialect fallback for backtick-quoted identifiers in base dialect parsing
tests/unit_tests/sql/parse_tests.py	Adds comprehensive test cases covering backtick-quoted identifiers with various SQL patterns

[Antonio-RiveroMartnez]

lgtm