将列值存储到 MySQL 存储过程的变量中
要声明变量,请在 MySQL 存储过程中使用 DECLARE。让我们首先创建一个表 -
mysql> create table DemoTable2034 -> ( -> StudentId int NOT NULL AUTO_INCREMENT PRIMARY KEY, -> StudentName varchar(20), -> StudentAge int -> ); Query OK, 0 rows affected (0.49 sec)
使用 insert 命令在表中插入一些记录 -
mysql> insert into DemoTable2034(StudentName,StudentAge) values('Chris',23);
Query OK, 1 row affected (0.10 sec)
mysql> insert into DemoTable2034(StudentName,StudentAge) values('David',21);
Query OK, 1 row affected (0.15 sec)
mysql> insert into DemoTable2034(StudentName,StudentAge) values('Robert',25);
Query OK, 1 row affected (0.15 sec)
mysql> insert into DemoTable2034(StudentName,StudentAge) values('Mike',19);
Query OK, 1 row affected (0.14 sec)使用 select 语句显示表中的所有记录 -
mysql> select *from DemoTable2034;
将生成以下输出 -
+-----------+-------------+------------+ | StudentId | StudentName | StudentAge | +-----------+-------------+------------+ | 1 | Chris | 23 | | 2 | David | 21 | | 3 | Robert | 25 | | 4 | Mike | 19 | +-----------+-------------+------------+ 4 rows in set (0.00 sec)
以下是要创建一个存储过程并将上述表的列值存储在存储过程变量中的查询 -
mysql> delimiter //
mysql> create procedure select_into_variable(id int)
-> begin
-> declare name varchar(50);
-> select StudentName into name from DemoTable2034 where StudentId=id;
-> select concat('Your Name is= ',name);
-> end
-> //
Query OK, 0 rows affected (0.09 sec)
mysql> delimiter ;调用存储过程 -
mysql> call select_into_variable(4);
将生成以下输出 -
+-------------------------------+
| concat('Your Name is= ',name) |
+-------------------------------+
| Your Name is= Mike |
+-------------------------------+
1 row in set (0.04 sec)
Query OK, 0 rows affected (0.06 sec)
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