regexp可以来自表列，而不是文本：

CREATE TABLE regexps (
    re VARCHAR(99)
);
INSERT INTO regexps (re)
    VALUES ('hii?|hell?o'), ('aloha'), ('bonjour');

SELECT CONCAT('matches ', re)
    FROM regexps
    WHERE "hi, y'all" REGEXP re;
SELECT CONCAT('matches ', re)
    FROM regexps
    WHERE "bonjour and aloha" REGEXP re;
SELECT CONCAT('matches ', re)
    FROM regexps
    WHERE "oops: high" REGEXP re;

...

mysql> SELECT * FROM regexps;
+-------------+
| re          |
+-------------+
| hii?|hell?o |
| aloha       |
| bonjour     |
+-------------+
3 rows in set (0.00 sec)

mysql>     SELECT CONCAT('matches ', re)
    ->         FROM regexps
    ->         WHERE "hi, y'all" REGEXP re;
+------------------------+
| CONCAT('matches ', re) |
+------------------------+
| matches hii?|hell?o    |
+------------------------+
1 row in set (0.01 sec)

mysql>     SELECT CONCAT('matches ', re)
    ->         FROM regexps
    ->         WHERE "bonjour and aloha" REGEXP re;
+------------------------+
| CONCAT('matches ', re) |
+------------------------+
| matches aloha          |
| matches bonjour        |
+------------------------+
2 rows in set (0.00 sec)

mysql>     SELECT CONCAT('matches ', re)
    ->         FROM regexps
    ->         WHERE "oops: high" REGEXP re;
+------------------------+
| CONCAT('matches ', re) |
+------------------------+
| matches hii?|hell?o    |
+------------------------+
1 row in set (0.00 sec)

我只想匹配hi或hii或helo或hello，然后回答“hello there” re 是 hii?|hell?o , answer 是 Hello There . 查询是

SELECT answer FROM regexps WHERE $input REGEXP re LIMIT 1

我加上 LIMIT 因为您可能遇到两个不同regexp匹配的情况。

您可以使用preg match和preg replace来测试您的正则表达式
例子：

$input = 'hii user';
$output = 'Hi there';
// If your regex matches
if(preg_match('/(hii?|hell?o)/', $input))
{
    // succes;
    // Replace the input by your answer
    echo preg_replace('/(hii?|hell?o)/', $output, $input); // returns Hi there user
}
else
{
    echo 'fail';
}