SQL query to process html tags ?

Hello,

I’ve used for a very long time an sql query provided by the blogger Lorelle, to search and replace strings of texts in the contents of my posts.

Here’s the script :

UPDATE wp_posts SET post_content = REPLACE (
post_content,
'text to replace',
'text taking place of the previous text');

However, when trying to replace
'(<strong>text</strong>, more text ? more text, <strong>more text</strong> ! :) )</p></blockquote> ',
with
'[sc name="shortcode1"]</p></blockquote>');

It didn’t work. Phpmyadmin found 0 matches (there should have been around 300).

I suppose something in the html tags broke the mysql query, but sadly, I’m not competent enough to find WHAT it might be.

A solution would be to export my wp_posts table and process it with a text file editor on my hard disks, and then reupload it, but this would be a long operation (compressed, my wp_posts is 6 MB large) and previous similar operations sometimes generated encoding issues with accentuated characters.
– I’d rather keep it inside phpmyadmin.

I’m asking “just in case”, perhaps the solution will be obvious for someone else…
Please, would you know if there’s a solution to manage to process the html tags in a mysql query ?

Thank you very much if you can help me, I’ll be grateful ??
Sabinou