ORACLE查看某张表的表结构

查看某张表的表结构：

   SELECT T1.TABLE_NAME,
       T1.COLUMN_NAME,
       T1.NULLABLE,
       T1.DATA_TYPE || '(' || T1.DATA_LENGTH || ')',
       T2.COMMENTS
  FROM USER_TAB_COLS T1, USER_COL_COMMENTS T2
 WHERE T1.TABLE_NAME = T2.TABLE_NAME
   AND T1.COLUMN_NAME = T2.COLUMN_NAME
   AND T1.TABLE_NAME = 'T_TRADE_DATATYPES';