Forbid to specify a database when creating a temporary table [#CLICKHOUSE-4294]

dbms/src/Common/ErrorCodes.cpp

@@ -416,6 +416,7 @@ namespace ErrorCodes
     extern const int CANNOT_SCHEDULE_TASK = 439;
     extern const int INVALID_LIMIT_EXPRESSION = 440;
     extern const int CANNOT_PARSE_DOMAIN_VALUE_FROM_STRING = 441;
+    extern const int BAD_DATABASE_FOR_TEMPORARY_TABLE = 442;
 
     extern const int KEEPER_EXCEPTION = 999;
     extern const int POCO_EXCEPTION = 1000;

dbms/src/Interpreters/InterpreterCreateQuery.cpp

@@ -63,6 +63,7 @@ namespace ErrorCodes
     extern const int DATABASE_ALREADY_EXISTS;
     extern const int QUERY_IS_PROHIBITED;
     extern const int THERE_IS_NO_DEFAULT_VALUE;
+    extern const int BAD_DATABASE_FOR_TEMPORARY_TABLE;
 }
 
 
@@ -547,6 +548,11 @@ BlockIO InterpreterCreateQuery::createTable(ASTCreateQuery & create)
         return executeDDLQueryOnCluster(query_ptr, context, std::move(databases));
     }
 
+    /// Temporary tables are created out of databases.
+    if (create.temporary && !create.database.empty())
+        throw Exception("Temporary tables cannot be inside a database. You should not specify a database for a temporary table.",
+            ErrorCodes::BAD_DATABASE_FOR_TEMPORARY_TABLE);
+
     String path = context.getPath();
     String current_database = context.getCurrentDatabase();