查询某个用户所有的表结构语句

select a.table_name as 表名,user_tab_comments.comments as 表名备注,a.column_name as 列名,
  a.data_type as 类型,
  decode(a.data_type, 'NUMBER', a.data_precision, a.data_length) as 长度,
a.data_scale as 小数位数,
  f.comments as 注释,
  a.nullable as 是否允许空,
  a.data_default as 缺省值,
  decode(e.key, 'Y', 'Y', 'N') as 外键
  from user_tab_columns a,user_col_comments f,user_tab_comments,
  (select b.table_name,
  b.index_name,
  b.uniqueness,
  c.column_name,
  decode(d.constraint_name, 'R', 'Y', 'N') key
  from user_indexes b,
  user_ind_columns c,
  (select constraint_name
  from user_constraints
  where constraint_type = 'P') d
  where b.index_name = c.index_name
  and b.index_name = d.constraint_name(+)) e
 where a.table_name = e.table_name(+)
  and a.column_name = e.column_name(+)
  and a.table_name = f.table_name
  and a.column_name = f.column_name
  and a.table_name = user_tab_comments.table_name
  --and a.table_name = 'T_EDR_CON'
--and a.table_name not in('PLAN_TABLE','T_COMMAND_PARAM')
 order by a.table_name