ClickHouse/dbms/src/Parsers/ASTSelectQuery.h
2017-08-12 00:01:28 +03:00

90 lines
2.8 KiB
C++

#pragma once
#include <Parsers/IAST.h>
#include <Parsers/ASTQueryWithOutput.h>
#include <Core/Names.h>
namespace DB
{
struct ASTTablesInSelectQueryElement;
/** SELECT query
*/
class ASTSelectQuery : public ASTQueryWithOutput
{
public:
ASTSelectQuery() = default;
ASTSelectQuery(const StringRange range_);
/** Get the text that identifies this element. */
String getID() const override { return "SelectQuery"; };
/// Check for the presence of the `arrayJoin` function. (Not capital `ARRAY JOIN`.)
static bool hasArrayJoin(const ASTPtr & ast);
/// Does the query contain an asterisk?
bool hasAsterisk() const;
/// Rename the query columns to the same names as in the original query.
void renameColumns(const ASTSelectQuery & source);
/// Rewrites select_expression_list to return only the required columns in the correct order.
void rewriteSelectExpressionList(const Names & required_column_names);
bool isUnionAllHead() const { return (prev_union_all == nullptr) && next_union_all != nullptr; }
ASTPtr clone() const override;
/// Get a deep copy of the first SELECT query tree.
std::shared_ptr<ASTSelectQuery> cloneFirstSelect() const;
private:
std::shared_ptr<ASTSelectQuery> cloneImpl(bool traverse_union_all) const;
public:
bool distinct = false;
ASTPtr with_expression_list;
ASTPtr select_expression_list;
ASTPtr tables;
ASTPtr prewhere_expression;
ASTPtr where_expression;
ASTPtr group_expression_list;
bool group_by_with_totals = false;
ASTPtr having_expression;
ASTPtr order_expression_list;
ASTPtr limit_by_value;
ASTPtr limit_by_expression_list;
ASTPtr limit_offset;
ASTPtr limit_length;
ASTPtr settings;
/// Compatibility with old parser of tables list. TODO remove
ASTPtr database() const;
ASTPtr table() const;
ASTPtr sample_size() const;
ASTPtr sample_offset() const;
ASTPtr array_join_expression_list() const;
const ASTTablesInSelectQueryElement * join() const;
bool array_join_is_left() const;
bool final() const;
void setDatabaseIfNeeded(const String & database_name);
void replaceDatabaseAndTable(const String & database_name, const String & table_name);
/// A double-linked list of SELECT queries inside a UNION ALL query.
/// The next SELECT query in the UNION ALL chain, if there is one
ASTPtr next_union_all;
/// Previous SELECT query in the UNION ALL chain (not inserted into children and not cloned)
/// The pointer is null for the following reasons:
/// 1. to prevent the occurrence of cyclic dependencies and, hence, memory leaks;
IAST * prev_union_all = nullptr;
protected:
void formatQueryImpl(const FormatSettings & settings, FormatState & state, FormatStateStacked frame) const override;
};
}