Question

嗨有没有人知道我应该如何创建一个触发器，它将从varchar和自动增量表创建一个唯一的id，包括来自用户输入的if else 我正在计划类似于下面的代码，但我收到错误1050表user_increment_table存在

DELIMITER ;
CREATE TRIGGER TG_ID
BEFORE INSERT ON userdatabase
FOR EACH ROW
BEGIN
  if User_department like "HR"
  then
  INSERT INTO user_increment_table VALUES (NULL);
  SET NEW.User_ID = CONCAT('HRU', LPAD(LAST_INSERT_ID(), 3, '0'));

Elseif U_role like "MARKETING" 
then  
  INSERT INTO user_increment_table VALUES (NULL);
  SET NEW.User_ID = CONCAT('MRK', LPAD(LAST_INSERT_ID(), 3, '0'));

END$$
DELIMITER ;

Answer 1

尝试：

mysql> DROP TABLE IF EXISTS `user_increment_table`, `userdatabase`;
Query OK, 0 rows affected (0.00 sec)

mysql> CREATE TABLE IF NOT EXISTS `userdatabase` (
    ->   `User_ID` VARCHAR(6),
    ->   `User_department` VARCHAR(255),
    ->   `U_role` VARCHAR(255)
    -> );
Query OK, 0 rows affected (0.00 sec)

mysql> CREATE TABLE IF NOT EXISTS `user_increment_table` (
    ->    `id` BIGINT UNSIGNED AUTO_INCREMENT PRIMARY KEY
    -> );
Query OK, 0 rows affected (0.00 sec)

mysql> DELIMITER //

mysql> CREATE TRIGGER `TG_ID` BEFORE INSERT ON `userdatabase`
    -> FOR EACH ROW
    -> BEGIN
    ->   IF NEW.`User_department` LIKE 'HR' THEN
    ->     INSERT INTO `user_increment_table` VALUES (NULL);
    ->     SET NEW.`User_ID` := CONCAT('HRU', LPAD(LAST_INSERT_ID(), 3, '0'));
    ->   ELSEIF NEW.`U_role` LIKE 'MARKETING' THEN  
    ->     INSERT INTO user_increment_table VALUES (NULL);
    ->     SET NEW.`User_ID` := CONCAT('MRK', LPAD(LAST_INSERT_ID(), 3, '0'));
    ->   END IF;
    -> END//
Query OK, 0 rows affected (0.00 sec)

mysql> DELIMITER ;

mysql> INSERT INTO `userdatabase` (`User_department`)
    -> VALUES ('HR');
Query OK, 1 row affected (0.00 sec)

mysql> INSERT INTO `userdatabase` (`U_role`)
    -> VALUES ('MARKETING');
Query OK, 1 row affected (0.00 sec)

mysql> SELECT
    ->   `User_ID`,
    ->   `User_department`,
    ->   `U_role`
    -> FROM
    ->   `userdatabase`;
+---------+-----------------+-----------+
| User_ID | User_department | U_role    |
+---------+-----------------+-----------+
| HRU001  | HR              | NULL      |
| MRK002  | NULL            | MARKETING |
+---------+-----------------+-----------+
2 rows in set (0.00 sec)

请参阅db-fiddle。

使用if else语句触发创建varchar自动增量

1 个答案: