How to create a MySQL hierarchical recursive query?
问题 I have a MySQL table which is as follows: id name parent_id 19 category1 0 20 category2 19 21 category3 20 22 category4 21 ... ... ... Now, I want to have a single MySQL query to which I simply supply the id [for instance say id=19 ] then I should get all its child ids [i.e. result should have ids '20,21,22'].... The hierarchy of the children is not known; it can vary.... I know how to do it using a for loop... but how to achieve the same using a single MySQL query? 回答1: For MySQL 8+: use the