fix(sql): handle backtick-quoted identifiers with base dialect (#36545)

Co-authored-by: Claude <noreply@anthropic.com>

superset/sql/parse.py

@@ -556,11 +556,28 @@ class SQLStatement(BaseSQLStatement[exp.Expression]):
     def _parse(cls, script: str, engine: str) -> list[exp.Expression]:
         """
         Parse helper.
+
+        When the base dialect (engine="base" or unknown engines) fails to parse SQL
+        containing backtick-quoted identifiers, we fall back to MySQL dialect which
+        supports backticks natively. This handles cases like "Other" database type
+        where users may have MySQL-compatible syntax with backtick-quoted table names.
         """
         dialect = SQLGLOT_DIALECTS.get(engine)
         try:
             statements = sqlglot.parse(script, dialect=dialect)
         except sqlglot.errors.ParseError as ex:
+            # If parsing fails with base dialect (or no dialect for unknown engines)
+            # and the script contains backticks, retry with MySQL dialect which
+            # supports backtick-quoted identifiers
+            if (dialect is None or dialect == Dialects.DIALECT) and "`" in script:
+                try:
+                    statements = sqlglot.parse(script, dialect=Dialects.MYSQL)
+                except sqlglot.errors.ParseError:
+                    # If MySQL dialect also fails, raise the original error
+                    pass
+                else:
+                    return statements
+
             kwargs = (
                 {
                     "highlight": ex.errors[0]["highlight"],

tests/unit_tests/sql/parse_tests.py

@@ -2977,3 +2977,96 @@ def test_has_subquery(sql: str, engine: str, expected: bool) -> None:
     Test the `has_subquery` method.
     """
     assert SQLStatement(sql, engine).has_subquery() == expected
+
+
+@pytest.mark.parametrize(
+    "sql, engine, expected_tables",
+    [
+        # Issue #31853: Backtick-quoted table names with "Other" database type
+        (
+            "SELECT * FROM database.`6`",
+            "base",
+            {Table(table="6", schema="database")},
+        ),
+        (
+            "SELECT * FROM database.`6` LIMIT 100",
+            "base",
+            {Table(table="6", schema="database")},
+        ),
+        # Backtick-quoted table name without schema
+        (
+            "SELECT * FROM `my_table`",
+            "base",
+            {Table(table="my_table")},
+        ),
+        # Backtick-quoted schema and table
+        (
+            "SELECT * FROM `my_schema`.`my_table`",
+            "base",
+            {Table(table="my_table", schema="my_schema")},
+        ),
+        # Complex query with multiple backtick-quoted identifiers
+        (
+            "SELECT `col1`, `col2` FROM `schema`.`table` WHERE `id` = 1",
+            "base",
+            {Table(table="table", schema="schema")},
+        ),
+        # Unknown engine should also fall back
+        (
+            "SELECT * FROM `table_name`",
+            "unknown-engine",
+            {Table(table="table_name")},
+        ),
+        # Multiple tables with backticks
+        (
+            "SELECT * FROM `t1` JOIN `t2` ON `t1`.id = `t2`.id",
+            "base",
+            {Table(table="t1"), Table(table="t2")},
+        ),
+        # Backticks in subquery
+        (
+            "SELECT * FROM (SELECT * FROM `inner_table`) AS sub",
+            "base",
+            {Table(table="inner_table")},
+        ),
+    ],
+)
+def test_backtick_quoted_identifiers_base_dialect(
+    sql: str, engine: str, expected_tables: set[Table]
+) -> None:
+    """
+    Test that backtick-quoted identifiers work with base dialect.
+
+    This is a regression test for issue #31853 where SQL parsing fails
+    with "Other" database type when using backtick-quoted table names.
+    The fix adds a fallback to MySQL dialect when parsing fails with
+    base dialect and backticks are present in the SQL.
+    """
+    script = SQLScript(sql, engine)
+    assert len(script.statements) == 1
+    assert script.statements[0].tables == expected_tables
+
+
+def test_backtick_normal_sql_still_works() -> None:
+    """
+    Test that normal SQL without backticks still works with base dialect.
+
+    This ensures the backtick fallback doesn't break normal parsing.
+    """
+    sql = "SELECT col1, col2 FROM my_schema.my_table WHERE id = 1"
+    script = SQLScript(sql, "base")
+    assert len(script.statements) == 1
+    assert script.statements[0].tables == {Table(table="my_table", schema="my_schema")}
+
+
+def test_backtick_invalid_sql_still_fails() -> None:
+    """
+    Test that invalid SQL with backticks still raises an error.
+
+    The fallback should only succeed when the MySQL dialect can parse
+    the SQL successfully.
+    """
+    # Invalid SQL that should fail even with MySQL dialect
+    sql = "SELECT * FROM `table` WHERE"
+    with pytest.raises(SupersetParseError):
+        SQLScript(sql, "base")