ClickHouse/src/Interpreters/ComparisonTupleEliminationVisitor.cpp
2023-03-21 16:23:09 +00:00

101 lines
2.6 KiB
C++

#include <Interpreters/ComparisonTupleEliminationVisitor.h>
#include <Parsers/ASTSelectQuery.h>
#include <Parsers/ASTFunction.h>
#include <Parsers/ASTLiteral.h>
namespace DB
{
namespace ErrorCodes
{
extern const int LOGICAL_ERROR;
}
namespace
{
ASTs splitTuple(const ASTPtr & node)
{
if (const auto * func = node->as<ASTFunction>(); func && func->name == "tuple")
return func->arguments->children;
if (const auto * literal = node->as<ASTLiteral>(); literal && literal->value.getType() == Field::Types::Tuple)
{
ASTs result;
const auto & tuple = literal->value.get<const Tuple &>();
for (const auto & child : tuple)
result.emplace_back(std::make_shared<ASTLiteral>(child));
return result;
}
return {};
}
ASTPtr concatWithAnd(const ASTs & nodes)
{
if (nodes.empty())
throw Exception(ErrorCodes::LOGICAL_ERROR, "Cannot concat empty list of nodes");
if (nodes.size() == 1)
return nodes[0];
auto result = makeASTFunction("and");
result->arguments->children = nodes;
return result;
}
class SplitTupleComparsionExpressionMatcher
{
public:
using Data = ComparisonTupleEliminationMatcher::Data;
static bool needChildVisit(const ASTPtr &, const ASTPtr &) { return true; }
static void visit(ASTPtr & ast, Data &)
{
auto * func = ast->as<ASTFunction>();
if (!func || func->arguments->children.size() != 2)
return;
if (func->name != "equals" && func->name != "notEquals")
return;
auto lhs = splitTuple(func->arguments->children[0]);
auto rhs = splitTuple(func->arguments->children[1]);
if (lhs.size() != rhs.size() || lhs.empty())
return;
ASTs new_args;
new_args.reserve(lhs.size());
for (size_t i = 0; i < lhs.size(); ++i)
{
new_args.emplace_back(makeASTFunction("equals", lhs[i], rhs[i]));
}
if (func->name == "notEquals")
ast = makeASTFunction("not", concatWithAnd(new_args));
else
ast = concatWithAnd(new_args);
}
};
using SplitTupleComparsionExpressionVisitor = InDepthNodeVisitor<SplitTupleComparsionExpressionMatcher, true>;
}
bool ComparisonTupleEliminationMatcher::needChildVisit(ASTPtr &, const ASTPtr &)
{
return true;
}
void ComparisonTupleEliminationMatcher::visit(ASTPtr & ast, Data & data)
{
auto * select_ast = ast->as<ASTSelectQuery>();
if (!select_ast || !select_ast->where())
return;
if (select_ast->where())
SplitTupleComparsionExpressionVisitor(data).visit(select_ast->refWhere());
}
}