Oracle獲取表字段名，字段類型，字段長度，注釋

SELECT b.comments as 注釋, a.column_name as 列名, a.data_type || '(' || a.data_length || ')' as 數據類型, a.nullable as 是否為空 FROM user_tab_columns a, user_col_comments b WHERE a.TABLE_NAME = '表名' and b.table_name = '表名' and a.column_name = b.column_name