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#include <Interpreters/ApplyWithGlobalVisitor.h>
#include <Parsers/ASTSelectQuery.h>
#include <Parsers/ASTSelectWithUnionQuery.h>
#include <Parsers/ASTSelectIntersectExceptQuery.h>
#include <Parsers/ASTWithAlias.h>
#include <Common/checkStackSize.h>
namespace DB
{
void ApplyWithGlobalVisitor::visit(ASTSelectQuery & select, const std::map<String, ASTPtr> & exprs, const ASTPtr & with_expression_list)
{
auto with = select.with();
if (with)
{
std::set<String> current_names;
for (const auto & child : with->children)
{
if (const auto * ast_with_alias = dynamic_cast<const ASTWithAlias *>(child.get()))
current_names.insert(ast_with_alias->alias);
}
for (const auto & with_alias : exprs)
{
if (!current_names.contains(with_alias.first))
with->children.push_back(with_alias.second->clone());
}
}
else
select.setExpression(ASTSelectQuery::Expression::WITH, with_expression_list->clone());
}
void ApplyWithGlobalVisitor::visit(
ASTSelectWithUnionQuery & selects, const std::map<String, ASTPtr> & exprs, const ASTPtr & with_expression_list)
{
for (auto & select : selects.list_of_selects->children)
{
if (ASTSelectWithUnionQuery * node_union = select->as<ASTSelectWithUnionQuery>())
{
visit(*node_union, exprs, with_expression_list);
}
else if (ASTSelectQuery * node_select = select->as<ASTSelectQuery>())
{
visit(*node_select, exprs, with_expression_list);
}
else if (ASTSelectIntersectExceptQuery * node_intersect_except = select->as<ASTSelectIntersectExceptQuery>())
{
visit(*node_intersect_except, exprs, with_expression_list);
}
}
}
void ApplyWithGlobalVisitor::visit(
ASTSelectIntersectExceptQuery & selects, const std::map<String, ASTPtr> & exprs, const ASTPtr & with_expression_list)
{
auto selects_list = selects.getListOfSelects();
for (auto & select : selects_list)
{
if (ASTSelectWithUnionQuery * node_union = select->as<ASTSelectWithUnionQuery>())
{
visit(*node_union, exprs, with_expression_list);
}
else if (ASTSelectQuery * node_select = select->as<ASTSelectQuery>())
{
visit(*node_select, exprs, with_expression_list);
}
else if (ASTSelectIntersectExceptQuery * node_intersect_except = select->as<ASTSelectIntersectExceptQuery>())
{
visit(*node_intersect_except, exprs, with_expression_list);
}
}
}
void ApplyWithGlobalVisitor::visit(ASTPtr & ast)
{
checkStackSize();
if (ASTSelectWithUnionQuery * node_union = ast->as<ASTSelectWithUnionQuery>())
{
if (auto * first_select = typeid_cast<ASTSelectQuery *>(node_union->list_of_selects->children[0].get()))
{
ASTPtr with_expression_list = first_select->with();
if (with_expression_list)
{
std::map<String, ASTPtr> exprs;
for (auto & child : with_expression_list->children)
{
if (auto * ast_with_alias = dynamic_cast<ASTWithAlias *>(child.get()))
exprs[ast_with_alias->alias] = child;
}
for (auto * it = node_union->list_of_selects->children.begin() + 1; it != node_union->list_of_selects->children.end(); ++it)
{
if (auto * union_child = (*it)->as<ASTSelectWithUnionQuery>())
visit(*union_child, exprs, with_expression_list);
else if (auto * select_child = (*it)->as<ASTSelectQuery>())
visit(*select_child, exprs, with_expression_list);
else if (auto * intersect_except_child = (*it)->as<ASTSelectIntersectExceptQuery>())
visit(*intersect_except_child, exprs, with_expression_list);
}
}
}
/*
* We need to visit all children recursively because the WITH statement may appear in the subquery at the nested level.
* Behavior of `WITH ... UNION ALL ...` should be the same at the top level and inside the subquery.
*
* For example:
* SELECT * FROM (WITH (SELECT ... ) AS t SELECT ... UNION ALL SELECT ...)
* ^^^^^^^^^^^^ should be visited ^^^^^^^^^^^^^^^^
* or inside `WHERE .. IN` clause:
* SELECT * FROM ... WHERE x IN (WITH (SELECT ... ) AS t SELECT ... UNION ALL SELECT ...)
*/
for (auto & child : node_union->list_of_selects->children)
visit(child);
}
else
{
// Other non-SELECT queries that contains SELECT children, such as EXPLAIN or INSERT
for (auto & child : ast->children)
visit(child);
}
}
}
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