Oralce recursive query

1. The basic syntax is: select... From where start with connect by; / /: filter condition, which is used to filter all returned records. / /: the qualification for re-starting the root node of the query result. /: join condition / / if prior in connect by prior is omitted, the query will not do deep recursion. two。 Query the current menu and all parent menus select t.* from s_menu t start with t.menu 510 'connect by prior t.fid = t.id3. Query up all superior menus (excluding the current menu) select t. * from s_menu t start with t. Connect by prior t.fid 510 'menu = t.id4. Query down the current menu and all subordinate menus select t. * from s_menu t start with t. Connect by prior t. Id = t.fid 5. Query down all subordinate menus (excluding the current menu) select t. * from s_menu t start with t. Connect by prior t. Id = t.fid6. Query the recursive path select t. Idret t. Namedepartment fiddirection substr (sys_connect_by_path (NAME,'- >'), 3) menu_pathfrom s_menu t start with t.name = 'system function' connect by prior t.id = t.fid order by t.id7. Hierarchical display of select t.idrpad LPad ('-', (level-1) * 4 ID'| -') | | lpad ('", 2) | | t.name | | rpad ('", 2) the key to upward and downward recursion is the last condition. If the parent ID equals ID, it recurses upward, and vice versa.

Reference: http://www.cnblogs.com/wanghonghu/archive/2012/08/31/2665945.html