Add prefer_column_name_to_alias settings (#22044)

src/Core/Settings.h

@@ -240,6 +240,7 @@ class IColumn;
     M(Bool, metrics_perf_events_enabled, false, "If enabled, some of the perf events will be measured throughout queries' execution.", 0) \
     M(String, metrics_perf_events_list, "", "Comma separated list of perf metrics that will be measured throughout queries' execution. Empty means all events. See PerfEventInfo in sources for the available events.", 0) \
     M(Float, opentelemetry_start_trace_probability, 0., "Probability to start an OpenTelemetry trace for an incoming query.", 0) \
+    M(Bool, prefer_column_name_to_alias, false, "Prefer using column names instead of aliases if possible.", 0) \
     \
     \
     /** Limits during query execution are part of the settings. \

src/Interpreters/QueryNormalizer.cpp

@@ -72,6 +72,12 @@ void QueryNormalizer::visit(ASTIdentifier & node, ASTPtr & ast, Data & data)
     if (!IdentifierSemantic::getColumnName(node))
         return;
 
+    if (data.settings.prefer_column_name_to_alias)
+    {
+        if (data.source_columns_set.find(node.name()) != data.source_columns_set.end())
+            return;
+    }
+
     /// If it is an alias, but not a parent alias (for constructs like "SELECT column + 1 AS column").
     auto it_alias = data.aliases.find(node.name());
     if (it_alias != data.aliases.end() && current_alias != node.name())
@@ -131,8 +137,20 @@ static bool needVisitChild(const ASTPtr & child)
 void QueryNormalizer::visit(ASTSelectQuery & select, const ASTPtr &, Data & data)
 {
     for (auto & child : select.children)
-        if (needVisitChild(child))
+    {
+        if (child == select.groupBy() || child == select.orderBy() || child == select.having())
+        {
+            bool old_setting = data.settings.prefer_column_name_to_alias;
+            data.settings.prefer_column_name_to_alias = false;
             visit(child, data);
+            data.settings.prefer_column_name_to_alias = old_setting;
+        }
+        else
+        {
+            if (needVisitChild(child))
+                visit(child, data);
+        }
+    }
 
     /// If the WHERE clause or HAVING consists of a single alias, the reference must be replaced not only in children,
     /// but also in where_expression and having_expression.

src/Interpreters/QueryNormalizer.h

@@ -4,6 +4,7 @@
 
 #include <Parsers/IAST.h>
 #include <Interpreters/Aliases.h>
+#include <Core/Names.h>
 
 namespace DB
 {
@@ -21,12 +22,15 @@ class QueryNormalizer
     {
         const UInt64 max_ast_depth;
         const UInt64 max_expanded_ast_elements;
+        bool prefer_column_name_to_alias;
 
         template <typename T>
         ExtractedSettings(const T & settings)
-        :   max_ast_depth(settings.max_ast_depth),
+            : max_ast_depth(settings.max_ast_depth)
-            max_expanded_ast_elements(settings.max_expanded_ast_elements)
+            , max_expanded_ast_elements(settings.max_expanded_ast_elements)
-        {}
+            , prefer_column_name_to_alias(settings.prefer_column_name_to_alias)
+        {
+        }
     };
 
 public:
@@ -36,7 +40,8 @@ public:
         using MapOfASTs = std::map<ASTPtr, ASTPtr>;
 
         const Aliases & aliases;
-        const ExtractedSettings settings;
+        const NameSet & source_columns_set;
+        ExtractedSettings settings;
 
         /// tmp data
         size_t level;
@@ -44,8 +49,9 @@ public:
         SetOfASTs current_asts;     /// vertices in the current call stack of this method
         std::string current_alias;  /// the alias referencing to the ancestor of ast (the deepest ancestor with aliases)
 
-        Data(const Aliases & aliases_, ExtractedSettings && settings_)
+        Data(const Aliases & aliases_, const NameSet & source_columns_set_, ExtractedSettings && settings_)
             : aliases(aliases_)
+            , source_columns_set(source_columns_set_)
             , settings(settings_)
             , level(0)
         {}

src/Interpreters/TreeRewriter.cpp

@@ -813,7 +813,14 @@ TreeRewriterResultPtr TreeRewriter::analyzeSelect(
     /// Optimizes logical expressions.
     LogicalExpressionsOptimizer(select_query, settings.optimize_min_equality_disjunction_chain_length.value).perform();
 
-    normalize(query, result.aliases, settings);
+    NameSet all_source_columns_set = source_columns_set;
+    if (table_join)
+    {
+        for (const auto & [name, _] : table_join->columns_from_joined_table)
+            all_source_columns_set.insert(name);
+    }
+
+    normalize(query, result.aliases, all_source_columns_set, settings);
 
     /// Remove unneeded columns according to 'required_result_columns'.
     /// Leave all selected columns in case of DISTINCT; columns that contain arrayJoin function inside.
@@ -871,7 +878,7 @@ TreeRewriterResultPtr TreeRewriter::analyze(
 
     TreeRewriterResult result(source_columns, storage, metadata_snapshot, false);
 
-    normalize(query, result.aliases, settings);
+    normalize(query, result.aliases, result.source_columns_set, settings);
 
     /// Executing scalar subqueries. Column defaults could be a scalar subquery.
     executeScalarSubqueries(query, context, 0, result.scalars, false);
@@ -896,7 +903,7 @@ TreeRewriterResultPtr TreeRewriter::analyze(
     return std::make_shared<const TreeRewriterResult>(result);
 }
 
-void TreeRewriter::normalize(ASTPtr & query, Aliases & aliases, const Settings & settings)
+void TreeRewriter::normalize(ASTPtr & query, Aliases & aliases, const NameSet & source_columns_set, const Settings & settings)
 {
     CustomizeCountDistinctVisitor::Data data_count_distinct{settings.count_distinct_implementation};
     CustomizeCountDistinctVisitor(data_count_distinct).visit(query);
@@ -945,7 +952,7 @@ void TreeRewriter::normalize(ASTPtr & query, Aliases & aliases, const Settings &
         FunctionNameNormalizer().visit(query.get());
 
     /// Common subexpression elimination. Rewrite rules.
-    QueryNormalizer::Data normalizer_data(aliases, settings);
+    QueryNormalizer::Data normalizer_data(aliases, source_columns_set, settings);
     QueryNormalizer(normalizer_data).visit(query);
 }
 

src/Interpreters/TreeRewriter.h

@@ -119,7 +119,7 @@ public:
 private:
     const Context & context;
 
-    static void normalize(ASTPtr & query, Aliases & aliases, const Settings & settings);
+    static void normalize(ASTPtr & query, Aliases & aliases, const NameSet & source_columns_set, const Settings & settings);
 };
 
 }

src/Interpreters/tests/gtest_cycle_aliases.cpp

@@ -20,6 +20,6 @@ TEST(QueryNormalizer, SimpleCycleAlias)
     aliases["b"] = parseQuery(parser, "a as b", 0, 0)->children[0];
 
     Settings settings;
-    QueryNormalizer::Data normalizer_data(aliases, settings);
+    QueryNormalizer::Data normalizer_data(aliases, {}, settings);
     EXPECT_THROW(QueryNormalizer(normalizer_data).visit(ast), Exception);
 }

tests/queries/0_stateless/01764_prefer_column_name_to_alias.reference

@@ -0,0 +1,3 @@
+4.5	9
+3	2
+3	3

tests/queries/0_stateless/01764_prefer_column_name_to_alias.sql

@@ -0,0 +1,8 @@
+SELECT avg(number) AS number, max(number) FROM numbers(10); -- { serverError 184 }
+SELECT sum(x) AS x, max(x) FROM (SELECT 1 AS x UNION ALL SELECT 2 AS x) t; -- { serverError 184 }
+select sum(C1) as C1, count(C1) as C2 from (select number as C1 from numbers(3)) as ITBL; -- { serverError 184 }
+
+set prefer_column_name_to_alias  = 1;
+SELECT avg(number) AS number, max(number) FROM numbers(10);
+SELECT sum(x) AS x, max(x) FROM (SELECT 1 AS x UNION ALL SELECT 2 AS x) t settings prefer_column_name_to_alias = 1;
+select sum(C1) as C1, count(C1) as C2 from (select number as C1 from numbers(3)) as ITBL settings prefer_column_name_to_alias = 1;