-----------+-----
1 row in set (0.00 sec)
mysql> select * from information_schema.columns where table_name="t_users";
# 关键是得到 column_name
+---------------+--------------+------------+-------------+------------------+----------------+-------------+-----------+----
| table_catalog | table_schema | table_name | column_name | ordinal_position | column_default | is_nullable | data_type | character_maximum_length |
character_octet_length | numeric_precision | numeric_scale | character_set_name | collation_name | column_type | column_key | extra | privileges |
column_comment |
+---------------+--------------+------------+-------------+------------------+----------------+-------------+-----------+----
| def | test | t_users | id | 1 | null | no | int | null | null | 10 | 0 | null |
null | int(11) | pri | auto_increment | select,insert,update,references | |
| def | test | t_users | name | 2 | null | no | text | 65535 | 65535 | null | null | gb2312
| gb2312_chinese_ci | text | | | select,insert,update,references | |
| def | test | t_users | password | 3 | null | no | text | 65535 | 65535 | null | null | gb2312
| gb2312_chinese_ci | text | | | select,insert,update,references | |
+---------------+--------------+------------+-------------+------------------+----------------+-------------+-----------+----
3 rows in set (0.01 sec)
mysql> select "id","password" from information_schema.columns where table_name="t_users";
# 注意当要查询的变量是常数的时候就是空查询，返回的一定就是你的查询常量，一般是在union的查询里确定
显示位置而用的
+----+----------+
| id | password |
+----+----------+
| id | password |
| id | password |
| id | password |
+----+----------+
3 rows in set (0.02 sec)
mysql> use test; #使用该数据库
database changed
mysql> select * from test;
error 1146 (42s02): table 'test.test' doesn't exist
mysql> select * from t_users;
empty set (0.00 sec)
这样就不需要再猜用户名和密码啦
insert into `t_users`(`id`, `name`, `password`) values (001,'张三疯','123456');
#插入一条记录之后
mysql> select * from t_users;
+----+--------+----------+
| id | name | password |
+----+--------+----------+
| 1 | 张三疯 | 123456 |
+----+--------+----------+
1 row in set (0.00 sec)
#如果没有权限添加，就只有逐位猜值啦
mysql> select count(*) from t_users where len(password)=12;
error 1305 (42000): function test.len does not exist
mysql>
# 二分查找法
#这里报错啦，该函数不存在，在mysql是length()在access里是len();
mysql> select count(*) from t_users where length(password)=12;
error 1305 (42000): function test.len does not exist
#首先确定了密码的长度
mysql> select password from t_users where length(password)<6;
empty set (0.00 sec)
mysql> select password from t_users where length(password)>6;
empty set (0.00 sec)
mysql> select password from t_users where length(password)=6;
+----------+
| password |
+----------+
| 123456 |
+----------+
1 row in set (0.00 sec)
#再进行逐位猜值
select * from t_users where asc(left(password,1))>0;
mysql> select password from t_users where left(password,1)<1;
empty set (0.00 sec)
mysql> select password from t_users where left(password,1)<2;
+----------+
| password |
+----------+
| 123456 |
+----------+
#函数执行并成功返回，说明第一位的值就是1
#或者直接查询密码:
mysql> select password from t_users where length('password')>0;
+----------+
| password |
+----------+
| 123456 |
+----------+
1 row in set (0.00 sec)
mysql> select password from t_users where ascii(left(password,1))<2;
empty set (0.00 sec)
#在mysql里面什么函数都要写全啦，在acess里直接就是asc();
mysql> sel |