摘要： -- 构建递归结构的表（数据是虚构的）drop table t;create table t( id int, name varchar(6), pid int);insert into tselect 1,'安徽',0 union allselect 2,'安庆',1 union allselect 3,'安庆市',2 union allselect 4,'怀宁县',2 union allselect 5,'潜山县',2 union allselect 6,'宿松县',2 union allsel 阅读全文