mysql 遍历字段并根据不同值归类

使用procedure，注意报表是否支持特定关键字（积木报表不支持注入关键字）

drop procedure if exists show_battery_info;
delimiter &&
CREATE PROCEDURE show_battery_info()

BEGIN
    DECLARE `@done` INT DEFAULT 0;
    DECLARE `@fieldName` VARCHAR(255);
    DECLARE SysTable CURSOR FOR SELECT DISTINCT kind FROM jupiter.battery_info;
    DECLARE CONTINUE HANDLER FOR NOT FOUND SET `@done` = 1;
    OPEN SysTable;
    read_loop:loop
        FETCH NEXT FROM SysTable INTO `@fieldName`;
        IF `@done` =1 THEN
            LEAVE read_loop;
        END IF;
        select * from 
            (select `@fieldName` as type, 
            case when capacity is null then 0 else capacity+0 end as value,
            DATE_FORMAT(reg_date,'%Y-%m-%d %H:%i:%s') as date 
            from jupiter.battery_info where `@fieldName`=kind order by date desc limit 50)t
        order by date;

        SET `@done` = 0;
    end loop read_loop;
    CLOSE SysTable;
END&&
delimiter ;
call show_battery_info();