本人新手，在mysql数据库写了一个存储过程，第一遍执行正常，第二遍执行就报错：Error Code: 1172. Result consisted of more than one row。存储过程如下：
CREATE DEFINER=root@localhost PROCEDURE generatePage(in sid varchar(3),in snum int,in mnum int,in jnum int,in setnum int)
BEGIN
declare i int;
declare gid varchar(10);
declare title1 text;
declare answer1 text;
declare title2 text;
declare answer2 text;
declare title3 text;
declare answer3 text;
set i= 0;
insert into generateinfo(subjectid,singlenum,multiplenum,judgmentnum,setnum,createtime) values(sid,snum,mnum,jnum,setnum,now());
select @@IDENTITY into gid from generateinfo;
while i<setnum Do
set title1 = "";
set answer1 = "";
set title2 = "";
set answer2 = "";
set title3 = "";
set answer3 = "";
if(snum>0) then
SELECT GROUP_CONCAT(a.id separator ','),GROUP_CONCAT(a.answer separator ',') into title1,answer1 FROM (SELECT q.* FROM questionbank q where q.qsubject = sid and q.qtype = '1' ORDER BY rand() LIMIT snum) as a limit 1;
end if;
if(mnum>0) then
SELECT GROUP_CONCAT(a.id separator ','),GROUP_CONCAT(a.answer separator ',') into title2,answer2 FROM (SELECT q.* FROM questionbank q where q.qsubject = sid and q.qtype = '2' ORDER BY rand() LIMIT mnum) as b limit 1;
end if;
if(jnum>0) then
SELECT GROUP_CONCAT(a.id separator ','),GROUP_CONCAT(a.answer separator ',') into title3,answer3 FROM (SELECT q.* FROM questionbank q where q.qsubject = sid and q.qtype = '3' ORDER BY rand() LIMIT jnum) as c limit 1;
end if;
if(title1!=""&&answer1!="") then
insert into pageinfo(generateid,questionid,questiontype,qanswer,setno) values(gid,title1,'1',answer1,i+1);
end if;
if(title2!=""&&answer2!="") then
insert into pageinfo(generateid,questionid,questiontype,qanswer,setno) values(gid,title2,'2',answer2,i+1);
end if;
if(title3!=""&&answer3!="") then
insert into pageinfo(generateid,questionid,questiontype,qanswer,setno) values(gid,title3,'3',answer3,i+1);
end if;
set i=i+1;
end while;
commit;
END
在网上查了很多资料，都是说需要在insert into 语句后面加上limit 1，但是我加上之后还是会报错，并且之前查询出来的结果是拼接数据，应该就只有一条。
求大神帮忙解决，谢谢！
