树形表的标记字段是什么
是parentID即父节点的id
如何查询树形表
- 当层级固定的时候可以用表的自连接查询
select
one.id one_id,
one.label one_label,
two.id two_id,
two.label two_label
from course_category one INNER JOIN course_category two on one.id=two.parentid
where one.parentid='1'
and one.is_show='1'
and two.is_show='1'
ORDER BY one.orderby,two.orderby;
- 如果想要灵活查询每个层级可以使用mysql中的递归方法，使用with recursive。
-- 递归查询
with recursive t1 as (
select * from course_category p where p.id= '1'
union all
select t.* from course_category t inner join t1 on t1.id = t.parentid
)
select * from t1 order by t1.id, t1.orderby;