Postgres- 级联到关系表的硬删除

Question

我正在编写 sql 查询（使用postgres 14 ）以从tags表中DELETE行：

标签表：

ID	team_id	姓名
1	91	开发团队

但是，它也应该CASCADE到team_member_tag表：

ID	team_member_id	tag_id
1	289	1

由team_member表加入：

ID	team_id	会员ID
289	91	1

我对其进行了测试，但似乎我的INNER JOIN出现故障。 我不知道我做错了什么？

我的查询：

            DELETE tag t, team_member_tag tmt
            FROM tag
            LEFT JOIN team_member_tag tmt ON t.id = tmt.team_member_id
            LEFT JOIN team_member tm ON tm.id = tmt.team_member_id 
            WHERE team_member.member_id = :teamId
            AND team_member.member_id = :teamMemberId

    $stmt->bindValue("teamId", 91 PDO::PARAM_INT);
    $stmt->bindValue("teamMemberId", 289, PDO::PARAM_INT);

我首先尝试使用SELECT ，它说查询没问题，但什么也没返回：

SELECT
    name
FROM tag as t
LEFT JOIN team_member_tag tmt ON t.id = tmt.team_member_id
LEFT JOIN team_member tm ON tm.id = tmt.team_member_id
WHERE name = 'Dev Team'
AND tmt.team_member_id = 289 AND tm.team_id = 91;

Answer 1

对于 postgres，您需要一个 CTE 来执行此操作，如果您没有级联引用，请参阅

    SELECT t.*, tmt.*
    FROM tag t
    INNER JOIN team_member_tag tmt ON t.id = tmt.tag_id
    INNER JOIN team_member ON tmt.team_member_id = team_member.id
    INNER JOIN member ON team_member.member_id = member.id
    WHERE team_member.team_id = 91
    AND team_member.member_id = 1;

ID	team_id	姓名	ID	team_member_id	tag_id
1	91	开发团队	1	289	1

 SELECT 1

WITH Bdeletes AS (
    DELETE FROM team_member_tag tmt 
  WHERE tmt.team_member_id IN (SELECT team_member.id
  FROM team_member
  WHERE team_member.team_id = 91
    AND team_member.member_id = 1) 
  returning tmt.tag_id 
)
DELETE from tag t
  where t.id
  IN( SELECT Tag_id FROM Bdeletes)

 DELETE 1

SELECT * FROM tag

ID	team_id	姓名

SELECT 0

SELECT * FROM team_member_tag

ID	team_member_id	tag_id

 SELECT 0

小提琴

但是，如果您添加一个 REFERENCE，您可以一次完成，添加更多引用也会从其他表中删除更多行

CREATE TABLE Tag 
    ("id" int  primary key, "team_id" int, "name" varchar(8))
;
    
INSERT INTO Tag 
    ("id", "team_id", "name")
VALUES
    (1, 91, 'Dev Team')

 CREATE TABLE

 INSERT 0 1

CREATE TABLE team_member_tag 
    ("id" int, "team_member_id" int, "tag_id" int references Tag (id) on delete cascade )
;
    
INSERT INTO team_member_tag 
    ("id", "team_member_id", "tag_id")
VALUES
    (1, 289, 1)
;

 CREATE TABLE

 INSERT 0 1

CREATE TABLE team_member 
    ("id" int, "team_id" int, "member_id" int)
;
    
INSERT INTO team_member 
    ("id", "team_id", "member_id")
VALUES
    (289, 91, 1)
;

 CREATE TABLE

 INSERT 0 1

CREATE TABLe member("id" int)

 CREATE TABLE

INSERT INTO member VALUES(1)

 INSERT 0 1

    SELECT t.*, tmt.*
    FROM tag t
    INNER JOIN team_member_tag tmt ON t.id = tmt.tag_id
    INNER JOIN team_member ON tmt.team_member_id = team_member.id
    INNER JOIN member ON team_member.member_id = member.id
    WHERE team_member.team_id = 91
    AND team_member.member_id = 1;

ID	team_id	姓名	ID	team_member_id	tag_id
1	91	开发团队	1	289	1

 SELECT 1

    DELETE FROM tag
  WHERE id IN
      (SELECT tag_id FROM  team_member_tag tmt 
  INNER JOIN team_member ON tmt.team_member_id = team_member.id
  WHERE team_member.team_id = 91
    AND team_member.member_id = 1) 

 DELETE 1

SELECT * FROM tag

ID	team_id	姓名

SELECT 0

SELECT * FROM team_member_tag

ID	team_member_id	tag_id

 SELECT 0

小提琴