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#include <Parsers/ASTSubquery.h>
#include <Parsers/queryToString.h>
#include <Storages/transformQueryForExternalDatabaseAnalyzer.h>
#include <Parsers/ASTSelectWithUnionQuery.h>
#include <Analyzer/InDepthQueryTreeVisitor.h>
#include <Columns/ColumnConst.h>
#include <Analyzer/QueryNode.h>
#include <Analyzer/ConstantNode.h>
#include <Analyzer/ConstantValue.h>
#include <DataTypes/DataTypesNumber.h>
namespace DB
{
namespace ErrorCodes
{
extern const int UNSUPPORTED_METHOD;
}
namespace
{
class PrepareForExternalDatabaseVisitor : public InDepthQueryTreeVisitor<PrepareForExternalDatabaseVisitor>
{
public:
using Base = InDepthQueryTreeVisitor<PrepareForExternalDatabaseVisitor>;
using Base::Base;
static void visitImpl(QueryTreeNodePtr & node)
{
auto * constant_node = node->as<ConstantNode>();
if (constant_node)
{
auto result_type = constant_node->getResultType();
if (isDate(result_type) || isDateTime(result_type) || isDateTime64(result_type))
{
/// Use string representation of constant date and time values
/// The code is ugly - how to convert artbitrary Field to proper string representation?
/// (maybe we can just consider numbers as unix timestamps?)
auto result_column = result_type->createColumnConst(1, constant_node->getValue());
const IColumn & inner_column = assert_cast<const ColumnConst &>(*result_column).getDataColumn();
WriteBufferFromOwnString out;
result_type->getDefaultSerialization()->serializeText(inner_column, 0, out, FormatSettings());
node = std::make_shared<ConstantNode>(std::make_shared<ConstantValue>(out.str(), result_type));
}
}
}
};
}
ASTPtr getASTForExternalDatabaseFromQueryTree(const QueryTreeNodePtr & query_tree)
{
auto new_tree = query_tree->clone();
PrepareForExternalDatabaseVisitor visitor;
visitor.visit(new_tree);
const auto * query_node = new_tree->as<QueryNode>();
auto query_node_ast = query_node->toAST({ .add_cast_for_constants = false, .fully_qualified_identifiers = false });
const IAST * ast = query_node_ast.get();
if (const auto * ast_subquery = ast->as<ASTSubquery>())
ast = ast_subquery->children.at(0).get();
const auto * union_ast = ast->as<ASTSelectWithUnionQuery>();
if (!union_ast)
throw Exception(ErrorCodes::UNSUPPORTED_METHOD, "QueryNode AST ({}) is not a ASTSelectWithUnionQuery", query_node_ast->getID());
if (union_ast->list_of_selects->children.size() != 1)
throw Exception(ErrorCodes::UNSUPPORTED_METHOD, "QueryNode AST is not a single ASTSelectQuery, got {}", union_ast->list_of_selects->children.size());
return union_ast->list_of_selects->children.at(0);
}
}
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