在 MySQL 中为枚举值设置自定义消息
mysqlmysqli database更新于 2024/12/16 2:20:17
使用 if else 为枚举设置自定义消息。让我们首先创建一个表 −
mysql> create table DemoTable1992
(
ClientId int NOT NULL AUTO_INCREMENT PRIMARY KEY,
ClientName varchar(20),
isActive ENUM('Y','N')
);
Query OK, 0 rows affected (0.89 sec)
使用 insert 命令在表中插入一些记录 −
mysql> insert into DemoTable1992(ClientName,isActive) values('Chris','N');
Query OK, 1 row affected (0.20 sec)
mysql> insert into DemoTable1992(ClientName,isActive) values('Bob','N');
Query OK, 1 row affected (0.08 sec)
mysql> insert into DemoTable1992(ClientName,isActive) values('David','Y');
Query OK, 1 row affected (0.14 sec)
mysql> insert into DemoTable1992(ClientName,isActive) values('Carol','N');
Query OK, 1 row affected (0.19 sec)
使用 select 语句显示表中的所有记录 −
mysql> select * from DemoTable1992;
这将产生以下输出 −
+----------+------------+----------+ | ClientId | ClientName | isActive | +----------+------------+----------+ | 1 | Chris | N | | 2 | Bob | N | | 3 | David | Y | | 4 | Carol | N | +----------+------------+----------+ 4 rows in set (0.00 sec)
这是使用 if else 设置自定义消息的查询
mysql> select ClientName,if(isActive='Y','Active Member','Not Active Member') as Result from DemoTable1992;
这将产生以下输出 −
+------------+-------------------+ | ClientName | Result | +------------+-------------------+ | Chris | Not Active Member | | Bob | Not Active Member | | David | Active Member | | Carol | Not Active Member | +------------+-------------------+ 4 rows in set (0.00 sec)
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