oracle如何查询表中所有字段

-- user_tab_columns 自定义的字段
SELECT column_name FROM user_tab_columns where table_name = upper('表名') 
-- user_tab_cols 包含oracle创建的隐藏字段
SELECT column_name FROM user_tab_cols where table_name = upper('表名') 

select Listagg(column_name, ',') WITHIN GROUP(ORDER BY column_name)
from user_tab_columns 
where table_name = upper('表名') 
--不想查询的字段名
and column_name not in ('字段名','字段名');

select table_name from user_tables; //当前用户拥有的表
select table_name from all_tables; //所有用户的表
select table_name from dba_tables; //包括系统表
select table_name from dba_tables where owner='用户名'
ALL_OBJECTS      describes all objects accessible to the current user.    描述当前用户有访问权限的所有对象 
DBA_OBJECTS     describes all objects in the database.                            描述了数据库中的所有对象 
USER_OBJECTS    describes all objects owned by the current user.        描述了当前用户所拥有的所有对象 

user_tab_comments;表注释
select * from user_tab_comments
user_tab_comments：table_name,table_type,comments

user_tab_comments;表注释
select * from user_tab_comments
user_tab_comments：table_name,table_type,comments

select * from user_col_comments
user_col_comments：table_name,column_name,comments

select table_name,column_name,comments from user_col_comments where table_name=‘JH';