ClickHouse/src/Interpreters/CollectJoinOnKeysVisitor.h
2020-08-05 12:31:59 +03:00

69 lines
2.1 KiB
C++

#pragma once
#include <Core/Names.h>
#include <Parsers/ASTFunction.h>
#include <Interpreters/InDepthNodeVisitor.h>
#include <Interpreters/DatabaseAndTableWithAlias.h>
#include <Interpreters/Aliases.h>
namespace DB
{
class ASTIdentifier;
class TableJoin;
namespace ASOF
{
enum class Inequality;
}
class CollectJoinOnKeysMatcher
{
public:
using Visitor = ConstInDepthNodeVisitor<CollectJoinOnKeysMatcher, true>;
struct Data
{
TableJoin & analyzed_join;
const TableWithColumnNamesAndTypes & left_table;
const TableWithColumnNamesAndTypes & right_table;
const Aliases & aliases;
const bool is_asof{false};
ASTPtr asof_left_key{};
ASTPtr asof_right_key{};
bool has_some{false};
void addJoinKeys(const ASTPtr & left_ast, const ASTPtr & right_ast, const std::pair<size_t, size_t> & table_no);
void addAsofJoinKeys(const ASTPtr & left_ast, const ASTPtr & right_ast, const std::pair<size_t, size_t> & table_no,
const ASOF::Inequality & asof_inequality);
void asofToJoinKeys();
};
static void visit(const ASTPtr & ast, Data & data)
{
if (auto * func = ast->as<ASTFunction>())
visit(*func, ast, data);
}
static bool needChildVisit(const ASTPtr & node, const ASTPtr &)
{
if (auto * func = node->as<ASTFunction>())
return func->name == "and";
return true;
}
private:
static void visit(const ASTFunction & func, const ASTPtr & ast, Data & data);
static void getIdentifiers(const ASTPtr & ast, std::vector<const ASTIdentifier *> & out);
static std::pair<size_t, size_t> getTableNumbers(const ASTPtr & expr, const ASTPtr & left_ast, const ASTPtr & right_ast, Data & data);
static const ASTIdentifier * unrollAliases(const ASTIdentifier * identifier, const Aliases & aliases);
static size_t getTableForIdentifiers(std::vector<const ASTIdentifier *> & identifiers, const Data & data);
};
/// Parse JOIN ON expression and collect ASTs for joined columns.
using CollectJoinOnKeysVisitor = CollectJoinOnKeysMatcher::Visitor;
}