层次查询

• 基本介绍
• 语法特性表
• PRIOR关键字介绍
• CONNECT_BY_ROOT关键字介绍
• SYS_CONNECT_BY_PATH函数介绍
• LEVEL伪列
• CONNECT_BY_ISLEAF伪列
• CONNECT_BY_ISCYCLE伪列
• SELECT: CONNECT BY
• SELECT: START WITH
• SELECT: ORDER SIBLINGS BY