Search for string within text column in MySQL
You could probably use the LIKE
clause to do some simple string matching:
SELECT * FROM items WHERE items.xml LIKE '%123456%'
If you need more advanced functionality, take a look at MySQL's fulltext-search functions here: http://dev.mysql.com/doc/refman/5.1/en/fulltext-search.html
Using like might take longer time so use full_text_search:
SELECT * FROM items WHERE MATCH(items.xml) AGAINST ('your_search_word')