Copilot commented on code in PR #34583:
URL: https://github.com/apache/superset/pull/34583#discussion_r2258583452
##########
superset/db_engine_specs/mssql.py:
##########
@@ -163,6 +164,33 @@ def extract_error_message(cls, ex: Exception) -> str:
)
return f"{cls.engine} error: {cls._extract_error_message(ex)}"
+ @classmethod
+ def adjust_query_for_offset(cls, qry: Select) -> Select:
+ """
+ Modify SQLAlchemy query to add ORDER BY when OFFSET is present.
+
+ MSSQL requires an ORDER BY clause when using OFFSET. If no ORDER BY
+ is present but OFFSET is specified, we add a default ORDER BY clause.
+ """
+ # Check if this query has OFFSET but no ORDER BY by inspecting query
structure
+ try:
+ # Try to access the internal query structure safely
+ has_offset = getattr(qry, "_offset", None) is not None
+ has_order_by = bool(getattr(qry, "_order_by_clauses", ()))
+
+ if has_offset and not has_order_by:
+ if qry.selected_columns:
+ first_column = list(qry.selected_columns)[0]
+ qry = qry.order_by(first_column)
+ else:
+ # Fallback to literal if no columns are available
+ qry = qry.order_by(cast(literal("1"), String))
Review Comment:
Using a cast literal for ordering is unusual and may cause performance
issues. Consider using a more standard approach like `text('1')` or ordering by
a constant expression that doesn't require casting.
```suggestion
qry = qry.order_by(literal(1))
```
##########
superset/db_engine_specs/mssql.py:
##########
@@ -163,6 +164,33 @@ def extract_error_message(cls, ex: Exception) -> str:
)
return f"{cls.engine} error: {cls._extract_error_message(ex)}"
+ @classmethod
+ def adjust_query_for_offset(cls, qry: Select) -> Select:
+ """
+ Modify SQLAlchemy query to add ORDER BY when OFFSET is present.
+
+ MSSQL requires an ORDER BY clause when using OFFSET. If no ORDER BY
+ is present but OFFSET is specified, we add a default ORDER BY clause.
+ """
+ # Check if this query has OFFSET but no ORDER BY by inspecting query
structure
+ try:
+ # Try to access the internal query structure safely
+ has_offset = getattr(qry, "_offset", None) is not None
+ has_order_by = bool(getattr(qry, "_order_by_clauses", ()))
+
+ if has_offset and not has_order_by:
+ if qry.selected_columns:
+ first_column = list(qry.selected_columns)[0]
Review Comment:
The condition `qry.selected_columns` may not work as expected for all
SQLAlchemy Select objects. This attribute might not exist or behave
consistently across different SQLAlchemy versions. Consider using `qry.columns`
or a more robust method to check for selected columns.
```suggestion
# Try to get the selected columns in a version-independent
way
selected_columns = (
getattr(qry, "selected_columns", None)
or getattr(qry, "exported_columns", None)
or getattr(qry, "_raw_columns", None)
)
if selected_columns:
first_column = list(selected_columns)[0]
```
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