text: --  @testpoint:opengauss关键字existing(非保留)，作为视图名
  
  
  --关键字existing作为视图名，不带引号，创建成功
  CREATE or replace VIEW existing AS
  SELECT * FROM pg_tablespace WHERE spcname = 'pg_default';
  drop view existing;
  
  --关键字existing作为视图名，加双引号，创建成功
  CREATE  or replace VIEW "existing" AS
  SELECT * FROM pg_tablespace WHERE spcname = 'pg_default';
  drop VIEW "existing";
  
  --关键字existing作为视图名，加单引号，合理报错
  CREATE or replace VIEW 'existing' AS
  SELECT * FROM pg_tablespace WHERE spcname = 'pg_default';
  
  --关键字existing作为视图名，加反引号，合理报错
  CREATE or replace VIEW `existing` AS
  SELECT * FROM pg_tablespace WHERE spcname = 'pg_default';
  
  