feat(sqlserver): add datetime interval expression formatting

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

Author: vistart

src/rhosocial/activerecord/backend/impl/sqlserver/dialect.py

@@ -274,6 +274,44 @@ def get_server_version(self) -> Tuple[int, int, int]:
         """Return the SQL Server version this dialect is configured for."""
         return self.version
 
+    def format_date_trunc_expression(self, expr: "Any") -> Tuple[str, Tuple]:
+        source_sql, source_params = expr.source.to_sql()
+        field = expr.field.value.upper()
+        if field in {"YEAR", "MONTH", "DAY", "HOUR", "MINUTE", "SECOND"}:
+            sql = f"DATETRUNC({field}, {source_sql})"
+        else:
+            raise UnsupportedFeatureError(self.name, f"date_trunc({expr.field.value})")
+        return self._apply_value_expression_modifiers(sql, source_params, expr)
+
+    def format_interval_expression(self, expr: "Any") -> Tuple[str, Tuple]:
+        raise UnsupportedFeatureError(
+            self.name,
+            "standalone INTERVAL expression",
+            "Use date_add() or date_sub() for SQL Server date arithmetic.",
+        )
+
+    def format_datetime_add_expression(self, expr: "Any") -> Tuple[str, Tuple]:
+        source_sql, source_params = expr.source.to_sql()
+        unit = expr.interval.unit.value.upper()
+        sql = f"DATEADD({unit}, ?, {source_sql})"
+        return self._apply_value_expression_modifiers(
+            sql, (expr.interval.value,) + source_params, expr
+        )
+
+    def format_datetime_subtract_expression(self, expr: "Any") -> Tuple[str, Tuple]:
+        source_sql, source_params = expr.source.to_sql()
+        unit = expr.interval.unit.value.upper()
+        sql = f"DATEADD({unit}, ?, {source_sql})"
+        return self._apply_value_expression_modifiers(
+            sql, (-expr.interval.value,) + source_params, expr
+        )
+
+    def format_datetime_diff_expression(self, expr: "Any") -> Tuple[str, Tuple]:
+        start_sql, start_params = expr.start.to_sql()
+        end_sql, end_params = expr.end.to_sql()
+        sql = f"DATEDIFF({expr.unit.value.upper()}, {start_sql}, {end_sql})"
+        return self._apply_value_expression_modifiers(sql, start_params + end_params, expr)
+
     def supports_collate_expression(self) -> bool:
         """SQL Server supports expression-level COLLATE."""
         return True