标签：des style blog color ar sp div on log
1. dual is a table that contains a single row.
2. The dual table has one VARCHAR2 column named dummy.
3. dual contains a single row with the value X.
desc dual; Name Null? Type DUMMY VARCHAR2(1)
标签：des style blog color ar sp div on log
原文地址：http://www.cnblogs.com/daishuguang/p/4059964.html
