ClickHouse/src/Interpreters/InterpreterShowTablesQuery.cpp
2020-04-03 18:14:31 +03:00

80 lines
2.1 KiB
C++

#include <IO/ReadBufferFromString.h>
#include <Parsers/ASTShowTablesQuery.h>
#include <Parsers/formatAST.h>
#include <Interpreters/Context.h>
#include <Interpreters/DatabaseCatalog.h>
#include <Interpreters/executeQuery.h>
#include <Interpreters/InterpreterShowTablesQuery.h>
#include <Common/typeid_cast.h>
#include <iomanip>
#include <sstream>
namespace DB
{
namespace ErrorCodes
{
extern const int SYNTAX_ERROR;
}
InterpreterShowTablesQuery::InterpreterShowTablesQuery(const ASTPtr & query_ptr_, Context & context_)
: query_ptr(query_ptr_), context(context_)
{
}
String InterpreterShowTablesQuery::getRewrittenQuery()
{
const auto & query = query_ptr->as<ASTShowTablesQuery &>();
/// SHOW DATABASES
if (query.databases)
return "SELECT name FROM system.databases";
if (query.temporary && !query.from.empty())
throw Exception("The `FROM` and `TEMPORARY` cannot be used together in `SHOW TABLES`", ErrorCodes::SYNTAX_ERROR);
String database = context.resolveDatabase(query.from);
DatabaseCatalog::instance().assertDatabaseExists(database);
std::stringstream rewritten_query;
rewritten_query << "SELECT name FROM system.";
if (query.dictionaries)
rewritten_query << "dictionaries ";
else
rewritten_query << "tables ";
rewritten_query << "WHERE ";
if (query.temporary)
{
if (query.dictionaries)
throw Exception("Temporary dictionaries are not possible.", ErrorCodes::SYNTAX_ERROR);
rewritten_query << "is_temporary";
}
else
rewritten_query << "database = " << std::quoted(database, '\'');
if (!query.like.empty())
rewritten_query << " AND name " << (query.not_like ? "NOT " : "") << "LIKE " << std::quoted(query.like, '\'');
else if (query.where_expression)
rewritten_query << " AND (" << query.where_expression << ")";
if (query.limit_length)
rewritten_query << " LIMIT " << query.limit_length;
return rewritten_query.str();
}
BlockIO InterpreterShowTablesQuery::execute()
{
return executeQuery(getRewrittenQuery(), context, true);
}
}