Merge pull request #25786 from kssenii/inconsisteny

Fix inconsistent behaviour of GROUP BY constant on empty set

src/Functions/materialize.h

@@ -29,6 +29,11 @@ public:
         return name;
     }
 
+    bool isInjective(const ColumnsWithTypeAndName & /*sample_columns*/) const override
+    {
+        return true;
+    }
+
     bool useDefaultImplementationForLowCardinalityColumns() const override { return false; }
 
     size_t getNumberOfArguments() const override

src/Interpreters/ExpressionAnalyzer.cpp

@@ -231,7 +231,6 @@ void ExpressionAnalyzer::analyzeAggregation()
 
     if (has_aggregation)
     {
-
         /// Find out aggregation keys.
         if (select_query)
         {
@@ -252,6 +251,8 @@ void ExpressionAnalyzer::analyzeAggregation()
                     /// Constant expressions have non-null column pointer at this stage.
                     if (node->column && isColumnConst(*node->column))
                     {
+                        select_query->group_by_with_constant_keys = true;
+
                         /// But don't remove last key column if no aggregate functions, otherwise aggregation will not work.
                         if (!aggregate_descriptions.empty() || size > 1)
                         {
@@ -288,6 +289,11 @@ void ExpressionAnalyzer::analyzeAggregation()
         else
             aggregated_columns = temp_actions->getNamesAndTypesList();
 
+        /// Constant expressions are already removed during first 'analyze' run.
+        /// So for second `analyze` information is taken from select_query.
+        if (select_query)
+            has_const_aggregation_keys = select_query->group_by_with_constant_keys;
+
         for (const auto & desc : aggregate_descriptions)
             aggregated_columns.emplace_back(desc.column_name, desc.function->getReturnType());
     }

src/Interpreters/ExpressionAnalyzer.h

@@ -65,6 +65,7 @@ struct ExpressionAnalyzerData
 
     bool has_aggregation = false;
     NamesAndTypesList aggregation_keys;
+    bool has_const_aggregation_keys = false;
     AggregateDescriptions aggregate_descriptions;
 
     WindowDescriptions window_descriptions;
@@ -309,6 +310,7 @@ public:
     bool hasTableJoin() const { return syntax->ast_join; }
 
     const NamesAndTypesList & aggregationKeys() const { return aggregation_keys; }
+    bool hasConstAggregationKeys() const { return has_const_aggregation_keys; }
     const AggregateDescriptions & aggregates() const { return aggregate_descriptions; }
 
     const PreparedSets & getPreparedSets() const { return prepared_sets; }

src/Interpreters/InterpreterSelectQuery.cpp

@@ -2041,7 +2041,7 @@ void InterpreterSelectQuery::executeAggregation(QueryPlan & query_plan, const Ac
         settings.group_by_two_level_threshold,
         settings.group_by_two_level_threshold_bytes,
         settings.max_bytes_before_external_group_by,
-        settings.empty_result_for_aggregation_by_empty_set,
+        settings.empty_result_for_aggregation_by_empty_set || (keys.empty() && query_analyzer->hasConstAggregationKeys()),
         context->getTemporaryVolume(),
         settings.max_threads,
         settings.min_free_disk_space_for_temporary_data,

src/Parsers/ASTSelectQuery.h

@@ -44,6 +44,7 @@ public:
     bool group_by_with_totals = false;
     bool group_by_with_rollup = false;
     bool group_by_with_cube = false;
+    bool group_by_with_constant_keys = false;
     bool limit_with_ties = false;
 
     ASTPtr & refSelect()    { return getExpression(Expression::SELECT); }

tests/queries/0_stateless/01414_optimize_any_bug.reference

@@ -1 +0,0 @@
-0

tests/queries/0_stateless/01925_test_group_by_const_consistency.reference

@@ -0,0 +1 @@
+0

tests/queries/0_stateless/01925_test_group_by_const_consistency.sql

@@ -0,0 +1,2 @@
+SELECT 1 as a, count() FROM numbers(10)　WHERE 0 GROUP BY a;
+SELECT count() FROM numbers(10) WHERE 0