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MySQL存储过程详解

news 2025/8/24 7:31:27

一、存储过程核心概念

1.1 定义与特性

存储过程是预编译的SQL语句集合，存储在数据库中，通过指定名称调用。其核心特性包括：

预编译执行：首次执行后编译结果缓存，后续调用直接执行
参数化设计：支持IN/OUT/INOUT三种参数类型
事务控制：内置事务管理能力，确保数据一致性
权限控制：可定义执行权限，增强安全性

1.2 MySQL 8.0新增特性

增强型条件处理：支持更复杂的异常处理逻辑
安全增强：默认使用DEFINER权限模式
性能优化：改进的编译缓存机制，提升执行效率

二、高级语法详解

2.1 参数深度解析

CREATE PROCEDURE calc_bonus(IN emp_id INT,OUT bonus DECIMAL(10,2),INOUT performance INT
)
BEGIN-- 基于绩效计算奖金SET bonus = performance * 1000;SET performance = performance + 1; -- 绩效等级提升
END;

2.2 游标高级应用

CREATE PROCEDURE process_orders()
BEGINDECLARE done INT DEFAULT FALSE;DECLARE order_id INT;DECLARE order_cursor CURSOR FOR SELECT id FROM orders WHERE status = 'pending';DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = TRUE;OPEN order_cursor;read_loop: LOOPFETCH order_cursor INTO order_id;IF done THENLEAVE read_loop;END IF;-- 处理每个订单CALL process_order(order_id);END LOOP;CLOSE order_cursor;
END;

2.3 异常处理机制

CREATE PROCEDURE safe_transfer(IN from_acc INT,IN to_acc INT,IN amount DECIMAL(10,2)
)
BEGINDECLARE EXIT HANDLER FOR SQLEXCEPTIONBEGINROLLBACK;RESIGNAL;END;START TRANSACTION;UPDATE accounts SET balance = balance - amount WHERE id = from_acc;UPDATE accounts SET balance = balance + amount WHERE id = to_acc;COMMIT;
END;

三、性能优化实战

3.1 索引优化策略

-- 创建覆盖索引
CREATE INDEX idx_orders_status_date 
ON orders(status, order_date) INCLUDE (total_amount);-- 存储过程中使用索引提示
SELECT /*+ INDEX(orders idx_orders_status_date) */ * FROM orders WHERE status = 'completed';

3.2 批量处理优化

CREATE PROCEDURE batch_update(IN data JSON)
BEGININSERT INTO temp_table (id, value)VALUES (JSON_UNQUOTE(JSON_EXTRACT(data, '$[0].id')), JSON_UNQUOTE(JSON_EXTRACT(data, '$[0].value'))),(JSON_UNQUOTE(JSON_EXTRACT(data, '$[1].id')), JSON_UNQUOTE(JSON_EXTRACT(data, '$[1].value')));UPDATE main_table INNER JOIN temp_table USING (id)SET main_table.value = temp_table.value;
END;

3.3 内存管理技巧

-- 调整会话级缓冲大小
SET SESSION sort_buffer_size = 256 * 1024 * 1024; -- 256MB
SET SESSION read_buffer_size = 128 * 1024 * 1024; -- 128MB-- 存储过程中使用临时表
CREATE TEMPORARY TABLE temp_results 
ENGINE=MEMORY 
AS SELECT * FROM heavy_query;

四、典型应用场景

4.1 数据迁移方案

CREATE PROCEDURE migrate_data()
BEGINDECLARE EXIT HANDLER FOR SQLEXCEPTIONBEGINROLLBACK;CALL log_error('Migration failed');END;START TRANSACTION;-- 禁用约束检查SET FOREIGN_KEY_CHECKS = 0;-- 批量插入数据INSERT INTO new_table SELECT * FROM old_table WHERE migration_flag = 0 LIMIT 1000;-- 更新迁移标记UPDATE old_table SET migration_flag = 1 WHERE id IN (SELECT id FROM new_table);-- 启用约束检查SET FOREIGN_KEY_CHECKS = 1;COMMIT;
END;

4.2 实时报表生成

CREATE PROCEDURE generate_report(IN report_date DATE)
BEGIN-- 创建临时报表表CREATE TEMPORARY TABLE IF NOT EXISTS temp_report ENGINE=InnoDB AS SELECT * FROM report_template WHERE 1=0;-- 插入聚合数据INSERT INTO temp_reportSELECT product_category,SUM(sales_amount) AS total_sales,COUNT(DISTINCT customer_id) AS unique_customersFROM salesWHERE sale_date BETWEEN report_date AND report_date + INTERVAL 7 DAYGROUP BY product_category;-- 生成CSV输出SELECT * FROM temp_report INTO OUTFILE '/tmp/weekly_report.csv'FIELDS TERMINATED BY ',' LINES TERMINATED BY '\n';
END;

五、调试与维护

5.1 调试技巧

-- 启用存储过程调试
SET GLOBAL log_output = 'TABLE';
SET GLOBAL slow_query_log = 'ON';
SET GLOBAL long_query_time = 0;-- 查看执行计划
EXPLAIN PROCEDURE analyze_performance;

5.2 版本控制

-- 创建带版本号的存储过程
CREATE PROCEDURE calc_tax_v2(IN amount DECIMAL(10,2),OUT tax DECIMAL(10,2)
)
SQL SECURITY DEFINER
COMMENT 'Version 2.1 - 2025-08-23'
BEGINSET tax = amount * 0.15; -- 税率更新为15%
END;

5.3 性能监控

-- 创建性能监控存储过程
CREATE PROCEDURE monitor_performance()
BEGIN-- 记录当前状态INSERT INTO performance_logSELECT NOW() AS timestamp,THREAD_ID,INFO AS query,DIGEST_TEXT AS normalized_query,TIMER_WAIT / 1000000000000 AS duration_secFROM performance_schema.events_statements_currentWHERE DIGEST_TEXT LIKE '%calc_tax%';-- 分析慢查询CALL analyze_slow_queries();
END;

六、最佳实践总结

事务边界控制：
- 保持事务短小精悍（<5秒）
- 避免在事务中执行用户交互

参数校验：

CREATE PROCEDURE validate_input(IN param INT)
BEGINIF param < 0 THENSIGNAL SQLSTATE '45000'SET MESSAGE_TEXT = 'Invalid parameter: must be positive';END IF;
END;