What is the MySQL query equivalent of PHP strip_tags?

Question

I have a large database which contains records that have <a> tags in them and I would like to remove them. Of course there is the method where I create a PHP script that selects all, uses strip_tags and updates the database, but this takes a long time. So how can I do this with a simple (or complicated) MySQL query?

Answer 1

MySQL >= 5.5 provides XML functions to solve your issue:

SELECT ExtractValue(field, '//text()') FROM table;

Reference: https://dev.mysql.com/doc/refman/5.5/en/xml-functions.html

Answer 2

Here you go:

CREATE FUNCTION `strip_tags`($str text) RETURNS text
BEGIN
    DECLARE $start, $end INT DEFAULT 1;
    LOOP
        SET $start = LOCATE("<", $str, $start);
        IF (!$start) THEN RETURN $str; END IF;
        SET $end = LOCATE(">", $str, $start);
        IF (!$end) THEN SET $end = $start; END IF;
        SET $str = INSERT($str, $start, $end - $start + 1, "");
    END LOOP;
END;

I made sure it removes mismatched opening brackets because they're dangerous, though it ignores any unpaired closing brackets because they're harmless.

mysql> select strip_tags('<span>hel<b>lo <a href="world">wo<>rld</a> <<x>again<.');
+----------------------------------------------------------------------+
| strip_tags('<span>hel<b>lo <a href="world">wo<>rld</a> <<x>again<.') |
+----------------------------------------------------------------------+
| hello world again.                                                   |
+----------------------------------------------------------------------+
1 row in set