MySQL PREPARE STATEMENT
预处理语句
PREPARE、EXECUTE、DEALLOCATE PREPARE

1.1 基本用法
CREATE PROCEDURE test()
BEGIN
SET @selectsql = ‘select * from app_user’;
– 预定义SQL
PREPARE stmt FROM @selectsql;
– 执行SQL
EXECUTE stmt;
– 释放连接
DEALLOCATE PREPARE stmt;
END;
1.2 传参用法
CREATE PROCEDURE test()
BEGIN
SET @selectsql = ‘select * from app_user where age > ? and age < ?’;
SET @a = 18;
SET @b = 30;
– 预定义SQL
PREPARE stmt FROM @selectsql;
– 传入两个会话变量来填充SQL中的 ? 并执行SQL
EXECUTE stmt USING @a, @b;
– 释放连接
DEALLOCATE PREPARE stmt;
END;