问题：在做项目的过程中遇到一个人问题：那就是将A表的deco字段的值，作为B表的列来展示，而且这些值的数据是从C表中取到的
方法：本来是想用，一个视图来列出deco字段里面的值和C表中的数据的，但是发现几张表的关联比较复杂（对应我来说）
使用单纯的select语句，是不能得到想要的效果的，在网上找了相关资料后，发现可以用游标来对查询结果集中的每一条
记录来处理，所以自己写出了如下的存储过程，这个存储过程会创建两张表，这两张表的简单关联就可以得到我想要的数据集。
代码：
/*创建过程*/DELIMITER //DROP PROCEDURE IF EXISTS update_report //CREATE PROCEDURE update_report()BEGINDECLARE done INT DEFAULT 0;DECLARE sql_alter VARCHAR(256) default '';DECLARE sql_str VARCHAR(256) default '';DECLARE a VARCHAR(200) DEFAULT '';DECLARE b VARCHAR(200) DEFAULT '';DECLARE c VARCHAR(200) DEFAULT '';DECLARE kpi_value VARCHAR(200) DEFAULT '';DECLARE mycursor CURSOR FOR SELECT id, name FROM dc_formula WHERE important=1;DECLARE projectcursor CURSOR FOR SELECT id from management_project;DECLARE CONTINUE HANDLER FOR NOT FOUND SET done=1;set @sql_alter='CREATE TABLE project_kpis (id int(11) NOT NULL PRIMARY key AUTO_INCREMENT,project_id VARCHAR(20) NOT NULL) ENGINE=MyISAM DEFAULT CHARSET=utf8';PREPARE sql_str from @sql_alter;EXECUTE sql_str;OPEN mycursor;REPEATFETCH mycursor INTO a,b;IF NOT done THENset b=REPLACE(b,'[','1');set b=REPLACE(b,']','1');set b=REPLACE(b,' ','_');set b=REPLACE(b,'/','dv');set @sql_alter=CONCAT('alter table project_kpis add ',b,' varchar(256)');PREPARE sql_str from @sql_alter;EXECUTE sql_str;END IF;UNTIL done END REPEAT;set done=0;CLOSE mycursor;OPEN projectcursor;projectcursor:LOOPFETCH projectcursor INTO c;IF done = 1 THENLEAVE projectcursor;END IF;insert into project_kpis(project_id) values(c);open mycursor;mycursor:LOOPFETCH mycursor INTO a,b;IF done = 1 THENLEAVE mycursor;end IF;set b=REPLACE(b,'[','1');set b=REPLACE(b,']','1');set b=REPLACE(b,' ','_');set b=REPLACE(b,'/','dv');set @project_id=c;set @formula_id=a;select case when value is NULL then '' else value END val into @kpi_value from v_dc_projectreport WHERE project_id=@project_id and formula_id=@formula_id and language_range='All_exclude_jp';SET @sql_alter = CONCAT('UPDATE project_kpis set ',b,'="',@kpi_value,'" where project_id=',@project_id);PREPARE sql_str from @sql_alter;EXECUTE sql_str;end LOOP mycursor;CLOSE mycursor; SET done=0;END LOOP projectcursor; CLOSE projectcursor;END //DELIMITER ;DELIMITER //DROP PROCEDURE if EXISTS kpi_report_pro //CREATE PROCEDURE kpi_report_pro()BEGINDROP table if EXISTS project_info;create table project_info as SELECT * from (SELECTA.*, B.project_year PROJECT_YEARFROM(SELECTid PROJECT_ID,NAME PROJECT_NAME,version VERSIONFROMmanagement_project) A LEFT JOIN dc_task B on A.PROJECT_ID=B.project_id GROUP BY A.PROJECT_ID) C;ALTER TABLE project_info ENGINE=MyISAM;DROP table if EXISTS project_kpis;call update_report();select * from project_info t,project_kpis p where t.PROJECT_ID=p.project_id;END //DELIMITER ;/* 调用存储过程，存储过程调用后产生两张表，project_kpis和project_info 执行完后会输出报表结果*/CALL kpi_report_pro()
，只有不断找寻机会的人才会及时把握机会。
