MYSQL查询通过在逗号分隔的字符串中查找其id来计算项的后代

My MYSQL database uses a tree-like system where each item can have an arbitrary number of descendants. Each item has a regular INT 'parent' column containing its parent as well as a VARCHAR 'parents' column which consists of a comma-separated string containing all of its ancestor's ids.My MYSQL database uses a tree-like system where