260 lines
6.9 KiB
Markdown
260 lines
6.9 KiB
Markdown
```sql
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-- 增删改
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INSERT INTO products (maker, model, type)
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VALUES ('I', '3008', 'printer');
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INSERT INTO sales (customer_id, model, quantity, day, paid, type_of_payment)
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VALUES ('1112223333', '3008', 2, '2024-01-01', 200, 'cash');
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INSERT INTO customers (customer_id, firstname, lastname, city, address, email)
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VALUES ('1112223333', 'Lisa', 'Smith', 'Dublin', '5 Main St.', 'lisa@example.com');
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-- 更新
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UPDATE pcs
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SET price = 2200
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WHERE model = '1001';
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UPDATE sales
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SET type_of_payment = 'visa credit'
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WHERE customer_id = '1122334455' AND model = '2010';
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UPDATE customers
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SET email = 'norah.jones@yahoo.com'
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WHERE customer_id = '9999999999';
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-- 删除
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DELETE FROM printers
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WHERE model = '3006';
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DELETE FROM sales
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WHERE day = '2013-12-17';
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DELETE FROM customers
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WHERE customer_id = '1231231231';
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-- 完成数据库新用户创建、
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CREATE USER `zds`
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-- 授权访问数据库、
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GRANT SELECT, UPDATE, INSERT ON TABLE sales TO zds;
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-- 授权用户传递权限（with grant option）
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GRANT SELECT ON sdut.sales TO zds WITH GRANT OPTION
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-- 收回用户的sales表更新权限
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REVOKE UPDATE ON sdut.sales FROM zds;
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-- 收回所有权限（彻底回收）
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REVOKE ALL PRIVILEGES ON sdut.sales FROM zds
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-- 删除创建的用户
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DROP USER zds;
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-- 触发器
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-- 1
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CREATE TABLE pcprice_log (
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log_id INT AUTO_INCREMENT PRIMARY KEY,
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model VARCHAR(10) NOT NULL,
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old_price DECIMAL(10,2) NOT NULL,
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new_price DECIMAL(10,2) NOT NULL
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);
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CREATE TRIGGER insert_pcpricelog_values_when_pc_price_changed
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AFTER UPDATE ON pcs
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FOR EACH ROW
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BEGIN
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IF OLD.price != NEW.price THEN
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INSERT INTO pcprice_log (model, old_price, new_price)
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VALUES (OLD.model, OLD.price, NEW.price);
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END IF;
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END;
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-- 测试
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-- INSERT INTO pcs (model, price, speed, ram, hd )
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-- VALUES ('1005', 200, 3.0, 8, 512);
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-- UPDATE pcs set price=22 WHERE model=1005
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-- 2定义AFTER行级触发器，当删除顾客表Customer中的一个顾客信息后，同时删除购买信息表Sales中该顾客的所有购买记录
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CREATE TRIGGER deleteCustomer
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after DELETE on customers
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for each row
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BEGIN
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DELETE FROM sales
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WHERE customer_id = OLD.customer_id;
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END
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-- -- 测试
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-- DELETE FROM customers WHERE customer_id=9999999999
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-- 3需要对在表上进行DML操作的用户进行安全检查，看是否具有合适的特权
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-- 权限表：存储用户可执行的DML权限（JSON数组格式，如["insert","update"]）
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CREATE TABLE IF NOT EXISTS userPrivilege (
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id INT PRIMARY KEY AUTO_INCREMENT,
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user_name VARCHAR(100) NOT NULL UNIQUE COMMENT '用户名（格式：user@host，如root@localhost，匹配CURRENT_USER()）',
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privilege JSON NOT NULL COMMENT '权限列表，JSON数组，值为"insert"/"update"/"delete"（统一小写）',
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create_time DATETIME DEFAULT CURRENT_TIMESTAMP COMMENT '权限创建时间'
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);
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-- 插入测试数据：给用户zds@localhost分配INSERT/UPDATE权限，不给DELETE权限
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INSERT INTO userPrivilege (user_name, privilege)
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VALUES ('zds@localhost', '["insert", "update"]');
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-- 权限表：存储用户可执行的DML权限（JSON数组格式，如["insert","update"]）
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CREATE TABLE IF NOT EXISTS userPrivilege (
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id INT PRIMARY KEY AUTO_INCREMENT,
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user_name VARCHAR(100) NOT NULL UNIQUE COMMENT '用户名（格式：user@host，如root@localhost，匹配CURRENT_USER()）',
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privilege JSON NOT NULL COMMENT '权限列表，JSON数组，值为"insert"/"update"/"delete"（统一小写）',
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create_time DATETIME DEFAULT CURRENT_TIMESTAMP COMMENT '权限创建时间'
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);
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-- 插入测试数据：给用户zds@localhost分配INSERT/UPDATE权限，不给DELETE权限
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INSERT INTO userPrivilege (user_name, privilege)
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VALUES ('zds@localhost', '["insert", "update"]');
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DELIMITER //
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CREATE TRIGGER trg_check_update_priv
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BEFORE UPDATE ON customers -- 同样可替换为目标表
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FOR EACH ROW
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BEGIN
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DECLARE user_priv JSON;
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DECLARE has_update INT DEFAULT 0;
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DECLARE curr_user VARCHAR(100) DEFAULT CURRENT_USER();
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-- 查询当前用户权限
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SELECT privilege INTO user_priv
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FROM userPrivilege
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WHERE user_name = curr_user;
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-- 判断是否有"update"权限
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IF user_priv IS NOT NULL THEN
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SET has_update = JSON_CONTAINS(user_priv, '"update"');
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END IF;
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-- 无权限抛错
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IF has_update = 0 THEN
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SIGNAL SQLSTATE '45000'
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SET MESSAGE_TEXT = CONCAT('安全检查失败：用户 [', curr_user, '] 无 ', TABLE_NAME, ' 表的 UPDATE 权限');
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END IF;
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END //
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DELIMITER ;
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DELIMITER //
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CREATE TRIGGER trg_check_delete_priv
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BEFORE DELETE ON customers -- 同样可替换为目标表
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FOR EACH ROW
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BEGIN
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DECLARE user_priv JSON;
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DECLARE has_delete INT DEFAULT 0;
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DECLARE curr_user VARCHAR(100) DEFAULT CURRENT_USER();
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-- 查询当前用户权限
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SELECT privilege INTO user_priv
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FROM userPrivilege
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WHERE user_name = curr_user;
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-- 判断是否有"delete"权限
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IF user_priv IS NOT NULL THEN
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SET has_delete = JSON_CONTAINS(user_priv, '"delete"');
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END IF;
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-- 无权限抛错
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IF has_delete = 0 THEN
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SIGNAL SQLSTATE '45000'
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SET MESSAGE_TEXT = CONCAT('安全检查失败：用户 [', curr_user, '] 无 ', TABLE_NAME, ' 表的 DELETE 权限');
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END IF;
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END //
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DELIMITER ;
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-- 4如果某个特定客户ID的购买记录从销售表中删除后，则从客户表中删除该客户。
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CREATE TRIGGER deleteCustomer_by4
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AFTER DELETE on sales
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for each row
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BEGIN
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DELETE FROM customers
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WHERE customer_id = OLD.customer_id;
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END
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CREATE TRIGGER discount AFTER INSERT ON sales FOR EACH ROW
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BEGIN
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DECLARE
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sum_paid DECIMAL ( 12, 2 );
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DECLARE
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discount DECIMAL ( 5, 2 );
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SELECT
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sum( paid ) INTO sum_paid
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FROM
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sales
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WHERE
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customer_id = NEW.customer_id;
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SELECT
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discount INTO discount
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FROM
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customers
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WHERE
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customer_id = NEW.customer_id;
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IF
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SUM_paid > 10000
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AND discount < 10.00 THEN
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UPDATE customers
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SET discount = 10.00
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WHERE
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customer_id = NEW.customer_id;
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END IF;
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END
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-- 6在客户中添加一个新的"AllPaid"栏，如果插入或更新或删除一个销售元组，那么修改该客户的"AllPaid"的值
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ALTER TABLE customers
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ADD COLUMN AllPaid DECIMAL(12,2) NOT NULL DEFAULT 0.00
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CREATE TRIGGER insert_value_customer
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AFTER INSERT on customers
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for each ROW
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BEGIN
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UPDATE customers
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set AllPaid =(
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SELECT SUM(paid) FROM sales
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WHERE customer_id = NEW.customer_id
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)
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WHERE customer_id = NEW.customer_id;
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END
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CREATE TRIGGER UPDATE_value_customer
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AFTER UPDATE on customers
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for each ROW
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BEGIN
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UPDATE customers
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set AllPaid =(
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SELECT SUM(paid) FROM sales
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WHERE customer_id = NEW.customer_id
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)
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WHERE customer_id = NEW.customer_id;
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END
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CREATE TRIGGER DELETE_value_customer
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AFTER DELETE on customers
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for each ROW
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BEGIN
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UPDATE customers
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set AllPaid =(
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SELECT SUM(paid) FROM sales
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WHERE customer_id = old.customer_id
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)
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WHERE customer_id = old.customer_id;
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END
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-- 测试
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```
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