这样就行了,你的有太多错误
select
DATE(aa.createtime) AS createTime,
count(*) as 个数
from sys_qrcode_t aa
left join sys_dy bb
on aa.person=bb.username
where 1=1
${if(len(结束时间)=0,"","and aa.createtime >='"+DATEDELTA(结束时间,-7)+"'")}
${if(len(结束时间)=0,"","and aa.createtime <'"+DATEDELTA(结束时间,1)+"'")}
group by DATE(aa.createtime)
