text: --  @testpoint:opengauss关键字If(非保留)，自定义数据类型名为explain
  --关键字explain作为数据类型不带引号，创建成功
  drop type if exists If;
  CREATE TYPE If AS (f1 int, f2 text);
  select typname from pg_type where typname ='If';
  drop type If;
  
  
  --关键字explain作为数据类型加双引号，创建成功
  drop type if exists "If";
  CREATE TYPE "If" AS (f1 int, f2 text);
  select typname from pg_type where typname ='If';
  drop type "If";
  
  --关键字explain作为数据类型加单引号，合理报错
  drop type if exists 'If';
  CREATE TYPE 'If' AS (f1 int, f2 text);
  select * from pg_type where typname ='If';
  drop type 'If';
  
  --关键字explain作为数据类型加反引号，合理报错
  drop type if exists `If`;
  CREATE TYPE `If` AS (f1 int, f2 text);
  select * from pg_type where typname =`If`;
  drop type `If`;