Bagaimana saya bisa Mengganti Hanya Hasil pertama di Fungsi SQL

Di MySQL <8.0, di mana regexp_replace() dan sejenisnya tidak didukung, Anda dapat menggunakan fungsi string:

update wp_comments
set comment_content = concat(
    substr(comment_content, 1, locate('XXX', comment_content) - 1),
    'MMM',
    substr(comment_content, locate('XXX', comment_content) + 3)
) 
where comment_id = 334 and locate('XXX', comment_content) > 0

Demo di DB Fiddle :

comment_id | comment_content                                                               
---------: | :-----------------------------------------------------------------------------
       334 | Hello MMM tomorrow we XXX will meeting in XXX Dubai, Do you want join us XXX ?