mysql 多行結合和拼接sql注入

select a1.email as email ,a1.bg ,IFNULL(a1.bg, a2.bg) from ( select * from test01 where sdate = '2019-09-11' ) a1 LEFT join (select * from test01 where sdate = '2019-09-10') a2 on a1.email=a2.email

sql輸入： String abc= " abc' or 1=1 or '' = ' "; String mm= " where email='"+abc+"'";