fix: dispatch GROUP BY in get_columns_changes_query_generic for T-SQL compatibility

Co-Authored-By: Itamar Hartstein <haritamar@gmail.com>

Author: devin-ai-integration[bot]

macros/edr/data_monitoring/schema_changes/get_columns_changes_query.sql

@@ -200,7 +200,7 @@
                         )
                     else null
                 end as test_results_description
-            from all_column_changes {{ dbt_utils.group_by(9) }}
+            from all_column_changes {{ elementary.schema_changes_query_group_by() }}
 
         )
 
@@ -242,6 +242,22 @@
     where lower(columns_snapshot.full_table_name) = lower('{{ full_table_name }}')
 {% endmacro %}
 
+{% macro schema_changes_query_group_by() %}
+    {{ return(adapter.dispatch("schema_changes_query_group_by", "elementary")()) }}
+{% endmacro %}
+
+{% macro default__schema_changes_query_group_by() %}
+    {{ dbt_utils.group_by(9) }}
+{% endmacro %}
+
+{% macro fabric__schema_changes_query_group_by() %}
+    {#- T-SQL does not support positional GROUP BY references and rejects
+        GROUP BY on constant expressions (e.g. 'schema_change').
+        Group by the 6 source columns from all_column_changes instead;
+        all 9 output columns are deterministic functions of these. -#}
+    group by full_table_name, change, column_name, data_type, pre_data_type, detected_at
+{% endmacro %}
+
 {% macro fabric__get_column_changes_from_baseline_cur(
     model_relation, full_table_name, model_baseline_relation
 ) %}