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#include <Interpreters/RequiredSourceColumnsVisitor.h>
#include <Common/typeid_cast.h>
#include <Core/Names.h>
#include <Parsers/IAST.h>
#include <Parsers/ASTIdentifier.h>
#include <Parsers/ASTFunction.h>
#include <Parsers/ASTSelectQuery.h>
#include <Parsers/ASTSubquery.h>
#include <Parsers/ASTTablesInSelectQuery.h>
#include <Parsers/ASTInterpolateElement.h>
namespace DB
{
namespace ErrorCodes
{
extern const int TYPE_MISMATCH;
extern const int NUMBER_OF_ARGUMENTS_DOESNT_MATCH;
}
std::vector<String> RequiredSourceColumnsMatcher::extractNamesFromLambda(const ASTFunction & node)
{
if (node.arguments->children.size() != 2)
throw Exception(ErrorCodes::NUMBER_OF_ARGUMENTS_DOESNT_MATCH, "lambda requires two arguments");
const auto * lambda_args_tuple = node.arguments->children[0]->as<ASTFunction>();
if (!lambda_args_tuple || lambda_args_tuple->name != "tuple")
throw Exception(ErrorCodes::TYPE_MISMATCH, "First argument of lambda must be a tuple");
std::vector<String> names;
for (auto & child : lambda_args_tuple->arguments->children)
{
const auto * identifier = child->as<ASTIdentifier>();
if (!identifier)
throw Exception(ErrorCodes::TYPE_MISMATCH, "lambda argument declarations must be identifiers");
names.push_back(identifier->name());
}
return names;
}
bool RequiredSourceColumnsMatcher::needChildVisit(const ASTPtr & node, const ASTPtr & child)
{
if (child->as<ASTSelectQuery>())
return false;
/// Processed. Do not need children.
if (node->as<ASTTableExpression>() || node->as<ASTArrayJoin>() || node->as<ASTSelectQuery>() || node->as<ASTInterpolateElement>())
return false;
if (const auto * f = node->as<ASTFunction>())
{
/// "lambda" visit children itself.
if (f->name == "lambda")
return false;
}
return true;
}
void RequiredSourceColumnsMatcher::visit(const ASTPtr & ast, Data & data)
{
/// results are columns
if (auto * t = ast->as<ASTIdentifier>())
{
visit(*t, ast, data);
return;
}
if (auto * t = ast->as<ASTFunction>())
{
/// "indexHint" is a special function for index analysis.
/// Everything that is inside it is not calculated. See KeyCondition
if (!data.visit_index_hint && t->name == "indexHint")
return;
data.addColumnAliasIfAny(*ast);
visit(*t, ast, data);
return;
}
/// results are tables
if (auto * t = ast->as<ASTTablesInSelectQueryElement>())
{
visit(*t, ast, data);
return;
}
if (auto * t = ast->as<ASTTableExpression>())
{
visit(*t, ast, data);
return;
}
if (auto * t = ast->as<ASTSelectQuery>())
{
visit(*t, ast, data);
return;
}
if (ast->as<ASTSubquery>())
{
return;
}
/// other
if (auto * t = ast->as<ASTArrayJoin>())
{
data.has_array_join = true;
visit(*t, ast, data);
return;
}
}
void RequiredSourceColumnsMatcher::visit(const ASTSelectQuery & select, const ASTPtr &, Data & data)
{
NameSet select_columns;
/// special case for top-level SELECT items: they are publics
for (auto & node : select.select()->children)
{
select_columns.insert(node->getAliasOrColumnName());
if (const auto * identifier = node->as<ASTIdentifier>())
data.addColumnIdentifier(*identifier);
else
data.addColumnAliasIfAny(*node);
}
if (auto interpolate_list = select.interpolate())
{
auto find_columns = [&data, &select_columns](IAST * function)
{
auto f_impl = [&data, &select_columns](IAST * fn, auto fi)
{
if (auto * ident = fn->as<ASTIdentifier>())
{
if (!select_columns.contains(ident->getColumnName()))
data.addColumnIdentifier(*ident);
return;
}
if (fn->as<ASTFunction>() || fn->as<ASTExpressionList>())
for (const auto & ch : fn->children)
fi(ch.get(), fi);
return;
};
f_impl(function, f_impl);
};
for (const auto & interpolate : interpolate_list->children)
find_columns(interpolate->as<ASTInterpolateElement>()->expr.get());
}
std::vector<ASTPtr *> out;
for (const auto & node : select.children)
{
// We should not go into WITH statement because all needed aliases are already expanded to
// the right place after normalization. And it might contain unused unknown columns.
if (node != select.select() && node != select.with())
Visitor(data).visit(node);
}
/// revisit select_expression_list (with children) when all the aliases are set
Visitor(data).visit(select.select());
}
void RequiredSourceColumnsMatcher::visit(const ASTIdentifier & node, const ASTPtr &, Data & data)
{
// FIXME(ilezhankin): shouldn't ever encounter
if (node.name().empty())
throw Exception(ErrorCodes::NUMBER_OF_ARGUMENTS_DOESNT_MATCH, "Expected not empty name");
if (!data.private_aliases.contains(node.name()))
data.addColumnIdentifier(node);
}
void RequiredSourceColumnsMatcher::visit(const ASTFunction & node, const ASTPtr &, Data & data)
{
/// Do not add formal parameters of the lambda expression
if (node.name == "lambda")
{
Names local_aliases;
for (const auto & name : extractNamesFromLambda(node))
if (data.private_aliases.insert(name).second)
local_aliases.push_back(name);
/// visit child with masked local aliases
RequiredSourceColumnsVisitor(data).visit(node.arguments->children[1]);
for (const auto & name : local_aliases)
data.private_aliases.erase(name);
}
}
void RequiredSourceColumnsMatcher::visit(const ASTTablesInSelectQueryElement & node, const ASTPtr &, Data & data)
{
for (const auto & child : node.children)
if (child->as<ASTTableJoin>())
data.has_table_join = true;
}
/// ASTIdentifiers here are tables. Do not visit them as generic ones.
void RequiredSourceColumnsMatcher::visit(const ASTTableExpression &, const ASTPtr &, Data &)
{
}
void RequiredSourceColumnsMatcher::visit(const ASTArrayJoin & node, const ASTPtr &, Data & data)
{
ASTPtr expression_list = node.expression_list;
if (!expression_list || expression_list->children.empty())
throw Exception(ErrorCodes::NUMBER_OF_ARGUMENTS_DOESNT_MATCH, "Expected not empty expression_list");
std::vector<ASTPtr *> out;
/// Tech debt. Ignore ARRAY JOIN top-level identifiers and aliases. There's its own logic for them.
for (auto & expr : expression_list->children)
{
data.addArrayJoinAliasIfAny(*expr);
if (const auto * identifier = expr->as<ASTIdentifier>())
{
data.addArrayJoinIdentifier(*identifier);
continue;
}
out.push_back(&expr);
}
for (ASTPtr * add_node : out)
Visitor(data).visit(*add_node);
}
}
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