对于以明文值分配密码的 SQL 语句，validate_password 会根据当前的密码策略检查密码，并在密码过弱时拒绝该密码（该语句将返回 ER_NOT_VALID_PASSWORD 错误）。这适用于 ALTER USER、CREATE USER 和 SET PASSWORD 语句。For SQL statements that assign a password supplied as a cleartext value, validate_password checks the password against the current password policy and rejects the password if it is weak (the statement returns an ER_NOT_VALID_PASSWORD error). This applies to the ALTER USER, CREATE USER, and SET PASSWORD statements.

对于 CREATE USER 语句，validate_password 要求必须提供密码，并且该密码必须符合密码策略。即使帐户最初被锁定，也同样适用，否则以后解锁帐户时将导致可以访问而无需符合策略的密码。For CREATE USER statements, validate_password requires that a password be given, and that it satisfies the password policy. This is true even if an account is locked initially because otherwise unlocking the account later would cause it to become accessible without a password that satisfies the policy.

validate_password 实现了一个 VALIDATE_PASSWORD_STRENGTH() SQL 函数，用于评估潜在密码的强度。该函数接受一个密码参数并返回一个从 0（弱）到 100（强）的整数。validate_password implements a VALIDATE_PASSWORD_STRENGTH() SQL function that assesses the strength of potential passwords. This function takes a password argument and returns an integer from 0 (weak) to 100 (strong).

validate_password 在以下语句中检查明文密码。在默认密码策略下，该策略要求密码至少为 8 个字符，该密码较弱，因此语句会产生错误：validate_password checks the cleartext password in the following statement. Under the default password policy, which requires passwords to be at least 8 characters long, the password is weak and the statement produces an error:

mysql> ALTER USER USER() IDENTIFIED BY 'abc';
ERROR 1819 (HY000): Your password does not satisfy the current
policy requirements

作为哈希值指定的密码不会被检查，因为原始密码值不可用于检查：Passwords specified as hashed values are not checked because the original password value is not available for checking:

mysql> ALTER USER 'jeffrey'@'localhost'
       IDENTIFIED WITH mysql_native_password
       AS '*0D3CED9BEC10A777AEC23CCC353A8C08A633045E';
Query OK, 0 rows affected (0.01 sec)

即使账户最初被锁定，该账户创建语句也会失败，因为它不包含满足当前密码策略的密码：This account-creation statement fails, even though the account is locked initially, because it does not include a password that satisfies the current password policy:

mysql> CREATE USER 'juanita'@'localhost' ACCOUNT LOCK;
ERROR 1819 (HY000): Your password does not satisfy the current
policy requirements

要检查密码，请使用 VALIDATE_PASSWORD_STRENGTH() 函数：To check a password, use the VALIDATE_PASSWORD_STRENGTH() function:

mysql> SELECT VALIDATE_PASSWORD_STRENGTH('weak');
+------------------------------------+
| VALIDATE_PASSWORD_STRENGTH('weak') |
+------------------------------------+
|                                 25 |
+------------------------------------+
mysql> SELECT VALIDATE_PASSWORD_STRENGTH('lessweak$_@123');
+----------------------------------------------+
| VALIDATE_PASSWORD_STRENGTH('lessweak$_@123') |
+----------------------------------------------+
|                                           50 |
+----------------------------------------------+
mysql> SELECT VALIDATE_PASSWORD_STRENGTH('N0Tweak$_@123!');
+----------------------------------------------+
| VALIDATE_PASSWORD_STRENGTH('N0Tweak$_@123!') |
+----------------------------------------------+
|                                          100 |
+----------------------------------------------+

LOW 策略仅测试密码长度。密码必须至少 8 个字符。要更改此长度，请修改 validate_password.length。LOW policy tests password length only. Passwords must be at least 8 characters long. To change this length, modify validate_password.length.

MEDIUM 策略增加了密码必须包含至少 1 个数字字符、1 个小写字母、1 个大写字母和 1 个特殊（非字母数字）字符的条件。要更改这些值，请修改 validate_password.number_count、validate_password.mixed_case_count 和 validate_password.special_char_count。MEDIUM policy adds the conditions that passwords must contain at least 1 numeric character, 1 lowercase character, 1 uppercase character, and 1 special (nonalphanumeric) character. To change these values, modify validate_password.number_count, validate_password.mixed_case_count, and validate_password.special_char_count.

STRONG 策略添加了一个条件，即长度为 4 或更长的密码子串不得与字典文件中的单词匹配（如果已指定字典文件）。要指定字典文件，请修改 validate_password.dictionary_file。STRONG policy adds the condition that password substrings of length 4 or longer must not match words in the dictionary file, if one has been specified. To specify the dictionary file, modify validate_password.dictionary_file.