ClickHouse/dbms/include/DB/Parsers/ASTOrderByElement.h

#pragma once

#include <DB/Parsers/IAST.h>


namespace DB
{

/** Element of expression with ASC or DESC,
  *  and possibly with COLLATE.
  */
class ASTOrderByElement : public IAST
{
public:
	int direction;	/// 1 for ASC, -1 for DESC
	int nulls_direction; /// Same as direction for NULLS LAST, opposite for NULLS FIRST.
	bool nulls_direction_was_explicitly_specified;

	/** Collation for locale-specific string comparison. If empty, then sorting done by bytes. */
	ASTPtr collation;

	ASTOrderByElement() = default;
	ASTOrderByElement(const StringRange range_,
		const int direction_, const int nulls_direction_, const bool nulls_direction_was_explicitly_specified_,
		ASTPtr & collation_)
		: IAST(range_),
		direction(direction_), nulls_direction(nulls_direction_),
		nulls_direction_was_explicitly_specified(nulls_direction_was_explicitly_specified_),
		collation(collation_) {}

	String getID() const override { return "OrderByElement"; }

	ASTPtr clone() const override { return std::make_shared<ASTOrderByElement>(*this); }

protected:
	void formatImpl(const FormatSettings & settings, FormatState & state, FormatStateStacked frame) const override;
};

}