#include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include namespace DB { namespace ErrorCodes { extern const int UNKNOWN_IDENTIFIER; extern const int UNSUPPORTED_JOIN_KEYS; extern const int LOGICAL_ERROR; } bool TranslateQualifiedNamesMatcher::Data::unknownColumn(size_t table_pos, const ASTIdentifier & identifier) const { const auto & table = tables[table_pos].table; auto nested1 = IdentifierSemantic::extractNestedName(identifier, table.table); auto nested2 = IdentifierSemantic::extractNestedName(identifier, table.alias); const String & short_name = identifier.shortName(); const Names & column_names = tables[table_pos].columns; for (const auto & known_name : column_names) { if (short_name == known_name) return false; if (nested1 && *nested1 == known_name) return false; if (nested2 && *nested2 == known_name) return false; } const Names & hidden_names = tables[table_pos].hidden_columns; for (const auto & known_name : hidden_names) { if (short_name == known_name) return false; if (nested1 && *nested1 == known_name) return false; if (nested2 && *nested2 == known_name) return false; } return !column_names.empty(); } bool TranslateQualifiedNamesMatcher::needChildVisit(ASTPtr & node, const ASTPtr & child) { /// Do not go to FROM, JOIN, subqueries. if (child->as() || child->as()) return false; /// Processed nodes. Do not go into children. if (node->as() || node->as()) return false; /// ASTSelectQuery + others return true; } void TranslateQualifiedNamesMatcher::visit(ASTPtr & ast, Data & data) { if (auto * t = ast->as()) visit(*t, ast, data); if (auto * t = ast->as()) visit(*t, ast, data); if (auto * t = ast->as()) visit(*t, ast, data); if (auto * node = ast->as()) visit(*node, ast, data); if (auto * node = ast->as()) visit(*node, ast, data); } void TranslateQualifiedNamesMatcher::visit(ASTIdentifier & identifier, ASTPtr &, Data & data) { if (IdentifierSemantic::getColumnName(identifier)) { String short_name = identifier.shortName(); bool allow_ambiguous = data.join_using_columns.count(short_name); if (auto best_pos = IdentifierSemantic::chooseTable(identifier, data.tables, allow_ambiguous)) { size_t table_pos = *best_pos; if (data.unknownColumn(table_pos, identifier)) { String table_name = data.tables[table_pos].table.getQualifiedNamePrefix(false); throw Exception("There's no column '" + identifier.name + "' in table '" + table_name + "'", ErrorCodes::UNKNOWN_IDENTIFIER); } IdentifierSemantic::setMembership(identifier, table_pos); /// In case if column from the joined table are in source columns, change it's name to qualified. /// Also always leave unusual identifiers qualified. const auto & table = data.tables[table_pos].table; if (table_pos && (data.hasColumn(short_name) || !isValidIdentifierBegin(short_name.at(0)))) IdentifierSemantic::setColumnLongName(identifier, table); else IdentifierSemantic::setColumnShortName(identifier, table); } } } /// As special case, treat count(*) as count(), not as count(list of all columns). void TranslateQualifiedNamesMatcher::visit(ASTFunction & node, const ASTPtr &, Data &) { ASTPtr & func_arguments = node.arguments; String func_name_lowercase = Poco::toLower(node.name); if (func_name_lowercase == "count" && func_arguments->children.size() == 1 && func_arguments->children[0]->as()) func_arguments->children.clear(); } void TranslateQualifiedNamesMatcher::visit(const ASTQualifiedAsterisk &, const ASTPtr & ast, Data & data) { if (ast->children.size() != 1) throw Exception("Logical error: qualified asterisk must have exactly one child", ErrorCodes::LOGICAL_ERROR); auto & ident = ast->children[0]; /// @note it could contain table alias as table name. DatabaseAndTableWithAlias db_and_table(ident); for (const auto & known_table : data.tables) if (db_and_table.satisfies(known_table.table, true)) return; throw Exception("Unknown qualified identifier: " + ident->getAliasOrColumnName(), ErrorCodes::UNKNOWN_IDENTIFIER); } void TranslateQualifiedNamesMatcher::visit(ASTTableJoin & join, const ASTPtr & , Data & data) { if (join.using_expression_list) Visitor(data).visit(join.using_expression_list); else if (join.on_expression) Visitor(data).visit(join.on_expression); } void TranslateQualifiedNamesMatcher::visit(ASTSelectQuery & select, const ASTPtr & , Data & data) { if (const auto * join = select.join()) extractJoinUsingColumns(join->table_join, data); /// If the WHERE clause or HAVING consists of a single qualified column, the reference must be translated not only in children, /// but also in where_expression and having_expression. if (select.prewhere()) Visitor(data).visit(select.refPrewhere()); if (select.where()) Visitor(data).visit(select.refWhere()); if (select.having()) Visitor(data).visit(select.refHaving()); } static void addIdentifier(ASTs & nodes, const DatabaseAndTableWithAlias & table, const String & column_name, AsteriskSemantic::RevertedAliasesPtr aliases) { String table_name = table.getQualifiedNamePrefix(false); auto identifier = std::make_shared(std::vector{table_name, column_name}); bool added = false; if (aliases && aliases->count(identifier->name)) { for (const String & alias : (*aliases)[identifier->name]) { nodes.push_back(identifier->clone()); nodes.back()->setAlias(alias); added = true; } } if (!added) nodes.emplace_back(identifier); } /// Replace *, alias.*, database.table.* with a list of columns. void TranslateQualifiedNamesMatcher::visit(ASTExpressionList & node, const ASTPtr &, Data & data) { const auto & tables_with_columns = data.tables; ASTs old_children; if (data.processAsterisks()) { bool has_asterisk = false; for (const auto & child : node.children) { if (child->as() || child->as()) { if (tables_with_columns.empty()) throw Exception("An asterisk cannot be replaced with empty columns.", ErrorCodes::LOGICAL_ERROR); has_asterisk = true; break; } else if (const auto * qa = child->as()) { visit(*qa, child, data); /// check if it's OK before rewrite has_asterisk = true; break; } } if (has_asterisk) { old_children.swap(node.children); node.children.reserve(old_children.size()); } } for (const auto & child : old_children) { if (const auto * asterisk = child->as()) { bool first_table = true; for (const auto & table : tables_with_columns) { for (const auto & column_name : table.columns) { if (first_table || !data.join_using_columns.count(column_name)) { addIdentifier(node.children, table.table, column_name, AsteriskSemantic::getAliases(*asterisk)); } } first_table = false; } } else if (const auto * asterisk_pattern = child->as()) { bool first_table = true; for (const auto & table : tables_with_columns) { for (const auto & column_name : table.columns) { if (asterisk_pattern->isColumnMatching(column_name) && (first_table || !data.join_using_columns.count(column_name))) { addIdentifier(node.children, table.table, column_name, AsteriskSemantic::getAliases(*asterisk_pattern)); } } first_table = false; } } else if (const auto * qualified_asterisk = child->as()) { DatabaseAndTableWithAlias ident_db_and_name(qualified_asterisk->children[0]); for (const auto & table : tables_with_columns) { if (ident_db_and_name.satisfies(table.table, true)) { for (const auto & column_name : table.columns) { addIdentifier(node.children, table.table, column_name, AsteriskSemantic::getAliases(*qualified_asterisk)); } break; } } } else node.children.emplace_back(child); } } /// 'select * from a join b using id' should result one 'id' column void TranslateQualifiedNamesMatcher::extractJoinUsingColumns(const ASTPtr ast, Data & data) { const auto & table_join = ast->as(); if (table_join.using_expression_list) { const auto & keys = table_join.using_expression_list->as(); for (const auto & key : keys.children) if (auto opt_column = tryGetIdentifierName(key)) data.join_using_columns.insert(*opt_column); else if (key->as()) data.join_using_columns.insert(key->getColumnName()); else { String alias = key->tryGetAlias(); if (alias.empty()) throw Exception("Wrong key in USING. Expected identifier or alias, got: " + key->getID(), ErrorCodes::UNSUPPORTED_JOIN_KEYS); data.join_using_columns.insert(alias); } } } void RestoreQualifiedNamesMatcher::Data::changeTable(ASTIdentifier & identifier) const { auto match = IdentifierSemantic::canReferColumnToTable(identifier, distributed_table); switch (match) { case IdentifierSemantic::ColumnMatch::AliasedTableName: case IdentifierSemantic::ColumnMatch::TableName: case IdentifierSemantic::ColumnMatch::DbAndTable: IdentifierSemantic::setColumnLongName(identifier, remote_table); break; default: break; } } bool RestoreQualifiedNamesMatcher::needChildVisit(ASTPtr &, const ASTPtr & child) { /// Do not go into subqueries if (child->as()) return false; // NOLINT return true; } void RestoreQualifiedNamesMatcher::visit(ASTPtr & ast, Data & data) { if (auto * t = ast->as()) visit(*t, ast, data); } void RestoreQualifiedNamesMatcher::visit(ASTIdentifier & identifier, ASTPtr &, Data & data) { if (IdentifierSemantic::getColumnName(identifier)) { if (IdentifierSemantic::getMembership(identifier)) { identifier.restoreCompoundName(); if (data.rename) data.changeTable(identifier); } } } }