Hierarchical query-层次查询中start with...connect by prior子句用法: connect by 是结构化查询中用到的,其基本语法是: select ... from tablename start with 条件1 connect by 条件2 where 条件3; 例: select level,empno,ename,job,mgr from emp start with empno=7566 or empno=7788 connect…
博客参考:https://www.cnblogs.com/jerryxing/articles/2339352.html start with connect by 层次查询(Hierarchical Queries) 语法: SELECT * FROM tableSTART WITH ID = 1CONNECT BY PRIOR PID = ID start with: 表示根记录的条件connect by: 指定了父记录行和子记录行之间的关系,在层次查询中,条件表达式必须使…