fix: SQL label missing for non-group-by queries (#29420)

(cherry picked from commit 179cf26)

superset/models/helpers.py

@@ -1672,7 +1672,9 @@ def get_sqla_query(  # pylint: disable=too-many-arguments,too-many-locals,too-ma
 
                 select_exprs.append(
                     self.convert_tbl_column_to_sqla_col(
-                        columns_by_name[selected], template_processor=template_processor
+                        columns_by_name[selected],
+                        template_processor=template_processor,
+                        label=_column_label,
                     )
                     if isinstance(selected, str) and selected in columns_by_name
                     else self.make_sqla_column_compatible(

tests/integration_tests/model_tests.py

@@ -592,6 +592,29 @@ def test_query_with_non_existent_metrics(self):
 
         self.assertTrue("Metric 'invalid' does not exist", context.exception)
 
+    def test_query_label_without_group_by(self):
+        tbl = self.get_table(name="birth_names")
+        query_obj = dict(
+            groupby=[],
+            columns=[
+                "gender",
+                {
+                    "label": "Given Name",
+                    "sqlExpression": "name",
+                    "expressionType": "SQL",
+                },
+            ],
+            filter=[],
+            is_timeseries=False,
+            granularity=None,
+            from_dttm=None,
+            to_dttm=None,
+            extras={},
+        )
+
+        sql = tbl.get_query_str(query_obj)
+        self.assertRegex(sql, r'name AS ["`]?Given Name["`]?')
+
     @pytest.mark.usefixtures("load_birth_names_dashboard_with_slices")
     def test_data_for_slices_with_no_query_context(self):
         tbl = self.get_table(name="birth_names")