Question

我有一个问题，我正在使用sqlite，

首先我创建了一个表：

 CREATE TABLE tree(
     id_tree integer PRIMARY KEY AUTOINCREMENT,
     id_boss TEXT,
     id_child TEXT,
     answ TEXT);

插入一些值：

 INSERT INTO tree(id_boss,id_child,answ) VALUES('1','8','T');
 INSERT INTO tree(id_boss,id_child,answ) VALUES('1',null,'F');
 INSERT INTO tree(id_boss,id_child,answ) VALUES('8','P1','T');
 INSERT INTO tree(id_boss,id_child,answ) VALUES('8','2','F');
 INSERT INTO tree(id_boss,id_child,answ) VALUES('2','P2','T');
 INSERT INTO tree(id_boss,id_child,answ) VALUES('2','P3','F');

并执行查询：

 WITH RECURSIVE
 ancestor(id) AS (
  VALUES('P3')
  UNION ALL
  SELECT tree.id_boss
  FROM tree JOIN ancestor ON tree.id_child = ancestor.id
  )
 SELECT id FROM ancestor;

结果是：

我的问题是，如何查询选择'T'值中的id_boss并忽略'F'中的所有内容？

结果应该是这样的：

  P3
  1

Answer 1

您无法从CTE内部过滤掉F条记录，因为这会破坏树中的连接。相反，您必须返回answ值，并在第二步中将其用作过滤器：

WITH RECURSIVE
ancestors(id, answ) AS (
  VALUES('P3', 'T')
  UNION ALL
  SELECT tree.id_boss, tree.answ
  FROM tree JOIN ancestors ON tree.id_child = ancestors.id
)
SELECT id FROM ancestors WHERE answ = 'T';

Answer 2

尝试：

带着回归祖先（id）AS（ VALUES（＆＃39; P3＆＃39;） UNION ALL SELECT tree.id_boss FROM tree JOIN祖先on tree.id_child = ancestor.id和tree。 ANSW =＆＃39; F＆＃39; ） SELECT id FROM ancestor;

选择特定值SQLite

2 个答案: