Basically, you are going about it the wrong way: SQL string handling is very poor and there is no full regex system built into SQL. For that reason, you are much, much better doing this in a presentation language when you add the data to the DB, instead of expecting it to be sorted out in the database later.
Databases are very good as storing, retrieving, and organising data, but they aren't good at manipulating data.
With a regex, it's not difficult, match this:
([^\<]+>)(\d+)
And replace it with this:
$1'$2'
But in SQL strings? It'll be horribly complicated, and difficult to maintain when you realise it should include ">=" as well ...
Do all data manipulation in your presentation language, where things are pretty simple so the DB data is already normalized and consistent!
Submit an article or tip