[\[:<:\]\]111,222,333\[\:>:\]
Prior to MySQL 8.0.4, MySQL used the Henry Spencer regular expression library to support regular expression operations, rather than International Components for Unicode (ICU).
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The Spencer library supports word-beginning and word-end boundary markers ([[:<:]] and [[:>:]] notation). ICU does not. For ICU, you can use \b to match word boundaries; double the backslash because MySQL interprets it as the escape character within strings.
\\b111,222,333\\b