ClickHouse/dbms/src/Interpreters/CollectJoinOnKeysVisitor.h

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#pragma once
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#include <Core/Names.h>
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#include <Parsers/ASTFunction.h>
#include <Interpreters/InDepthNodeVisitor.h>
#include <Interpreters/Aliases.h>
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namespace DB
{
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class ASTIdentifier;
struct AnalyzedJoin;
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class CollectJoinOnKeysMatcher
{
public:
using Visitor = ConstInDepthNodeVisitor<CollectJoinOnKeysMatcher, true>;
struct Data
{
AnalyzedJoin & analyzed_join;
const NameSet & source_columns;
const NameSet & joined_columns;
const Aliases & aliases;
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const bool is_asof;
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);
void asofToJoinKeys();
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};
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>())
if (func->name == "equals")
return false;
return true;
}
private:
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static void visit(const ASTFunction & func, const ASTPtr & ast, Data & data);
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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);
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[[noreturn]] static void throwSyntaxException(const String & msg);
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};
/// Parse JOIN ON expression and collect ASTs for joined columns.
using CollectJoinOnKeysVisitor = CollectJoinOnKeysMatcher::Visitor;
}