mysql如何删除父子表

CREATE TABLE parent (
    id INT PRIMARY KEY,
    name VARCHAR(255)
);

CREATE TABLE child (
    id INT PRIMARY KEY,
    parent_id INT,
    name VARCHAR(255),
    FOREIGN KEY (parent_id) REFERENCES parent(id)
);

INSERT INTO parent (id, name) VALUES (1, 'Parent 1');
INSERT INTO child (id, parent_id, name) VALUES (1, 1, 'Child 1');

-- 删除子表中的数据
DELETE FROM child WHERE parent_id = 1;

-- 删除父表中的数据
DELETE FROM parent WHERE id = 1;

-- 修改子表的外键约束，启用级联删除
ALTER TABLE child DROP FOREIGN KEY fk_child_parent;
ALTER TABLE child ADD CONSTRAINT fk_child_parent FOREIGN KEY (parent_id) REFERENCES parent(id) ON DELETE CASCADE;

-- 删除父表中的数据，子表中的相关数据也会被删除
DELETE FROM parent WHERE id = 1;