需求:有如下两张表,其中tb_web_app表中数据有十万甚至百万,另,tb_web_app表中的c_category_code关联表tb_system_category中的c_code字段。
- CREATE TABLE `tb_system_category` (
- `id` int(11) NOT NULL AUTO_INCREMENT,
- `c_parent_id` int(11) NOT NULL,
- `c_name` varchar(50) NOT NULL,
- `c_full_name` varchar(200) DEFAULT NULL,
- `c_code` varchar(50) NOT NULL,
- `c_describe` text,
- PRIMARY KEY (`id`)
- ) ENGINE=InnoDB AUTO_INCREMENT=123 DEFAULT CHARSET=utf8;
- CREATE TABLE `tb_web_app` (
- `id` int(11) NOT NULL AUTO_INCREMENT,
- `c_name` varchar(255) NOT NULL,
- `c_package_name` varchar(255) NOT NULL,
- `c_category_code` varchar(50) NOT NULL DEFAULT ‘0’,
- PRIMARY KEY (`id`)
- ) ENGINE=InnoDB AUTO_INCREMENT=138583 DEFAULT CHARSET=utf8;
要求分页查询tb_web_app表,并显示其c_category_code对应的c_full_name(来自tb_system_category)。
笔者先是使用sql联表语句进行查询,不外乎left join等语句的使用,结果发现执行速度巨慢无比,遂转成存储过程实现,存储过程代码如下所示:
- CREATE PROCEDURE findWebappAndCategory(IN cName VARCHAR(255), IN pName VARCHAR(255), IN cCategoryCodes VARCHAR(100), IN cID INTEGER, IN cType VARCHAR(50), IN startRow INTEGER, IN pageSize INTEGER)
- BEGIN
- DECLARE cRand VARCHAR(50) DEFAULT RAND();
- — 创建临时表
- CREATE TEMPORARY TABLE IF NOT EXISTS tb_system_temp_wac(
- id INTEGER,
- c_name varchar(255),
- c_package_name varchar(255),
- c_category_code varchar(50),
- categoryName VARCHAR(255),
- cRand VARCHAR(50)
- );
- — 按条件找到webapp
- CALL findWebapp(cName,pName,cCategoryCodes,cID,cType,startRow,pageSize,cRand);
- — 将找到的webapp的c_category_code的值进行替换
- CALL generateCategoryName(cRand);
- — 返回结果
- SET @mySql = CONCAT(‘select * from tb_system_temp_wac where cRand=\”,cRand,‘\”);
- PREPARE stmt FROM @mySql;
- EXECUTE stmt;
- END
- CREATE PROCEDURE findWebapp(IN cName VARCHAR(255), IN pName VARCHAR(255), IN cCategoryCodes VARCHAR(100), IN cID INTEGER, IN cType VARCHAR(50), IN startRow INTEGER, IN pageSize INTEGER, IN cRand VARCHAR(50))
- BEGIN
- DECLARE sqlStr VARCHAR(4000);
- IF cType = ‘count’ THEN
- SET sqlStr = ‘select count(id) from tb_web_app where 1=1 ‘;
- ELSE
- SET sqlStr = CONCAT(‘select id,c_name,c_package_name,c_category_code,c_category_code,\”,cRand,‘\’ from tb_web_app where 1=1 ‘);
- END IF;
- IF LENGTH(cName) > 0 THEN
- SET sqlStr = CONCAT(sqlStr,‘and c_name like \’%’,cName,‘%\’ ‘);
- END IF;
- IF LENGTH(pName) > 0 THEN
- SET sqlStr = CONCAT(sqlStr,‘and c_package_name like \’%’,pName,‘%\’ ‘);
- END IF;
- IF cID > 0 THEN
- SET sqlStr = CONCAT(sqlStr,‘and id=’,cID,‘ ‘);
- END IF;
- IF LENGTH(cCategoryCodes) > 0 THEN
- SET sqlStr = CONCAT(sqlStr,‘and c_category_code in(‘,cCategoryCodes,‘) ‘);
- END IF;
- IF cType != ‘count’ THEN
- SET sqlStr = CONCAT(‘insert into tb_system_temp_wac(id,c_name,c_package_name,c_category_code,categoryName,cRand) ‘,sqlStr,‘limit ‘,startRow,‘,’,pageSize);
- END IF;
- SET @mySql = sqlStr;
- PREPARE stmt FROM @mySql;
- EXECUTE stmt;
- END
- CREATE PROCEDURE generateCategoryName(IN c_rand VARCHAR(50))
- BEGIN
- DECLARE finished INTEGER DEFAULT 0;
- DECLARE thisCategoryName VARCHAR(20);
- DECLARE cur CURSOR FOR select categoryName from tb_system_temp_wac where cRand = c_rand;
- DECLARE CONTINUE HANDLER FOR NOT FOUND SET finished = 1;
- OPEN cur;
- FETCH cur INTO thisCategoryName;
- WHILE finished = 0 DO
- SET @mySql = CONCAT(‘update tb_system_temp_wac set categoryName=(select c_full_name from tb_system_category where c_code=\”,thisCategoryName,‘\’ limit 0,1) where c_category_code=\”,thisCategoryName,‘\’ and cRand=\”,c_rand,‘\”);
- PREPARE stmt FROM @mySql;
- EXECUTE stmt;
- FETCH cur INTO thisCategoryName;
- END WHILE;
- END