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Re-visit subquery for IN in CreateUniqueTableAliasesVisitor.

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This commit is contained in:
Nikolai Kochetov 2023-12-15 15:15:07 +00:00
parent 5c1ed3e2c2
commit fd64599127
1 changed files with 21 additions and 0 deletions
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21
src/Analyzer/createUniqueTableAliases.cpp
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@ -1,9 +1,11 @@
#include <memory>
#include <unordered_map>
#include <Analyzer/createUniqueTableAliases.h>
#include <Analyzer/FunctionNode.h>
#include <Analyzer/InDepthQueryTreeVisitor.h>
#include <Analyzer/IQueryTreeNode.h>
#include <Analyzer/LambdaNode.h>
#include <Analyzer/Utils.h>
namespace DB
{
@ -26,6 +28,7 @@ public:
void enterImpl(QueryTreeNodePtr & node)
{
auto node_type = node->getNodeType();
switch (node_type)
{
case QueryTreeNodeType::QUERY:
@ -90,6 +93,24 @@ public:
}
scope_nodes_stack.pop_back();
}
/// Here we revisit subquery for IN function. Reasons:
/// * For remote query execution, query tree may be traversed a few times.
/// In such a case, it is possible to get AST like
/// `IN ((SELECT ... FROM table AS __table4) AS __table1)` which result in
/// `Multiple expressions for the alias` exception
/// * Tables in subqueries could have different aliases => different three hashes,
/// which is important to be able to find a set in PreparedSets
/// See 01253_subquery_in_aggregate_function_JustStranger.
///
/// So, we revisit this subquery to make aliases stable.
/// This should be safe cause columns from IN subquery can't be used in main query anyway.
if (node->getNodeType() == QueryTreeNodeType::FUNCTION)
{
auto * function_node = node->as<FunctionNode>();
if (isNameOfInFunction(function_node->getFunctionName()))
CreateUniqueTableAliasesVisitor(getContext()).visit(function_node->getArguments().getNodes().back());
}
}
private: