mysql如何查询一个单表树形结构的数据
表结构如下
create table t1 (id number(5),name varchar(10),p_id number(5));insert into t1 values (1,'name_1',null);insert into t1 values (2,'name_2',1);insert into t1 values (3,'name_3',null);insert into t1 values (4,'name_4',1);insert into t1 values (5,'name_5',3);insert into t1 values (6,'name_6',1);insert into t1 values (7,'name_7',3);insert into t1 values (8,'name_8',4);insert into t1 values (9,'name_9',2);insert into t1 values (10,'name_10',1);
id name p_id-------------------------------1 1 name_1 2 2 name_2 13 9 name_9 24 4 name_4 15 8 name_8 46 6 name_6 17 10 name_10 18 3 name_3 9 5 name_5 310 7 name_7 3