mysql中游标的使用

BEGIN
#遍历占领野地表还原军队
#update armforce set number=num where troopsid=(select id from troops where isfrist=1 and cityid=cityid)
    DECLARE tId DECIMAL(21,0) default -1;#occupyWild表的TroopsId
        DECLARE cid DECIMAL(21,0) default -1;#occupyWild表的CityId
    DECLARE temp_tId DECIMAL(21,0) default -1;#occupyWild表的TroopsId
        DECLARE temp_cid DECIMAL(21,0) default -1;#occupyWild表的CityId
        DECLARE tId2 DECIMAL(21,0) default -1;#troops表的TroopsId
        DECLARE num0 int default 0;
        DECLARE num1 int default 0;
        DECLARE num2 int default 0;
        DECLARE num3 int default 0;
        DECLARE curl CURSOR FOR SELECT TroopsId,CityId FROM occupyWild order by TroopsId ASC;
        DECLARE CONTINUE HANDLER FOR SQLSTATE '' SET tId = -1;
        OPEN curl;
    FETCH curl INTO tId,cid;
    WHILE(tId<>-1) DO
            #说明：游标变量使用一次以后就会被清除
      #************************ 逻辑 START ************************
                set tId2=-1,temp_tId=-1,temp_cid=-1,num0=0,num1=0,num2=0,num3=0;
                set temp_tId=tId;
                set temp_cid=cid;
                select id into tId2 from Troops where isFrist=1 and CityId=temp_cid limit 1;#正常情况下只有一条数据
                select number into num0 from Armforce where TroopsId=temp_tId and ArmType=0;
                select number into num1 from Armforce where TroopsId=temp_tId and ArmType=1;
                select number into num2 from Armforce where TroopsId=temp_tId and ArmType=2;
                select number into num3 from Armforce where TroopsId=temp_tId and ArmType=3;
                update Armforce set Number=Number+num0 where TroopsId=tId2 and ArmType=0;#退回军队
                delete from Armforce where TroopsId=temp_tId and ArmType=0;#删除军队
                update Armforce set Number=Number+num1 where TroopsId=tId2 and ArmType=1;
                delete from Armforce where TroopsId=temp_tId and ArmType=1;
                update Armforce set Number=Number+num2 where TroopsId=tId2 and ArmType=2;
                delete from Armforce where TroopsId=temp_tId and ArmType=2;
                update Armforce set Number=Number+num3 where TroopsId=tId2 and ArmType=3;
                delete from Armforce where TroopsId=temp_tId and ArmType=3;

            #************************ 逻辑 END ************************

      FETCH curl into tId,cid;
    END WHILE;
    CLOSE curl;  

END