text: DROP TABLE IF EXISTS t;
  
  CREATE TABLE t(c1 int) ENGINE = Null;
  SELECT COUNT(1) from system.tables where name = 't' and database = 'default';
  
  CREATE TABLE IF NOT EXISTS t(c1 int) ENGINE = Null;
  CREATE TABLE t(c1 int) ENGINE = Null; -- {ErrorCode 4003}
  
  
  create table t2(a int,b int) engine=Memory;
  insert into t2 values(1,1),(2,2);
  select a+b from t2;
  
  create table t2(a int,b int) engine=NotExists; -- {ErrorCode 4003}
  
  DROP TABLE IF EXISTS t;
  DROP TABLE IF EXISTS t2;
  
  CREATE DATABASE db1;
  CREATE DATABASE db2;
  CREATE TABLE db1.test1(a INT, b INT);
  CREATE TABLE db2.test2 LIKE db1.test1;
  INSERT INTO db2.test2 VALUES (3, 5);
  SELECT a+b FROM db2.test2;
  DROP DATABASE db1;
  DROP DATABASE db2;
  