Merge branch 'master' of https://github.com/ClickHouse/ClickHouse into testflows_windows_functions_add_lag_and_lead_in_frame_tests

src/Interpreters/JoinToSubqueryTransformVisitor.cpp

@@ -91,7 +91,20 @@ public:
             {
                 if (should_add_column_predicate(column.name))
                 {
-                    auto identifier = std::make_shared<ASTIdentifier>(std::vector<String>{it->first, column.name});
+                    ASTPtr identifier;
+                    if (it->first.empty())
+                        /// We want tables from JOIN to have aliases.
+                        /// But it is possible to set joined_subquery_requires_alias = 0,
+                        /// and write a query like `select * FROM (SELECT 1), (SELECT 1), (SELECT 1)`.
+                        /// If so, table name will be empty here.
+                        ///
+                        /// We cannot create compound identifier with empty part (there is an assert).
+                        /// So, try our luck and use only column name.
+                        /// (Rewriting AST for JOIN is not an efficient design).
+                        identifier = std::make_shared<ASTIdentifier>(column.name);
+                    else
+                        identifier = std::make_shared<ASTIdentifier>(std::vector<String>{it->first, column.name});
+
                     new_select_expression_list->children.emplace_back(std::move(identifier));
                 }
             }

src/Parsers/ASTIdentifier.cpp

@@ -80,7 +80,7 @@ void ASTIdentifier::setShortName(const String & new_name)
     name_parts = {new_name};
 
     bool special = semantic->special;
-    //how about keep the semantic info here, such as table
+    /// How about keep the semantic info here, such as table
     auto table = semantic->table;
 
     *semantic = IdentifierSemanticImpl();
@@ -116,8 +116,14 @@ void ASTIdentifier::formatImplWithoutAlias(const FormatSettings & settings, Form
             if (i != 0)
                 settings.ostr << '.';
 
-            if (name_parts[i].empty())
+            /// Some AST rewriting code, like IdentifierSemantic::setColumnLongName,
-                children[j++]->formatImpl(settings, state, frame);
+            /// does not respect children of identifier.
+            /// Here we also ignore children if they are empty.
+            if (name_parts[i].empty() && j < children.size())
+            {
+                children[j]->formatImpl(settings, state, frame);
+                ++j;
+            }
             else
                 format_element(name_parts[i]);
         }
@@ -125,7 +131,7 @@ void ASTIdentifier::formatImplWithoutAlias(const FormatSettings & settings, Form
     else
     {
         const auto & name = shortName();
-        if (name.empty())
+        if (name.empty() && !children.empty())
             children.front()->formatImpl(settings, state, frame);
         else
             format_element(name);

tests/queries/0_stateless/01890_cross_join_explain_crash.reference

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

tests/queries/0_stateless/01890_cross_join_explain_crash.sql

@@ -0,0 +1,8 @@
+SET joined_subquery_requires_alias = 0;
+select * FROM (SELECT 1), (SELECT 1), (SELECT 1); -- { serverError 352 }
+
+-- This queries work by luck.
+-- Feel free to remove then if it is the only failed test.
+select * from (select 2), (select 1) as a, (select 1) as b;
+select * from (select 1) as a, (select 2), (select 1) as b;
+select * from (select 1) as a, (select 1) as b, (select 2);