Have a small table with the replacements and use a simple `SELECT` to get the corresponding value. I think this is safer because it will only replace a value once. The nested `REPLACE` runs the risk of accidentally replacing what's already replaced, unless that's a requirement in some cases. For example, changing 'dogs' to 'cats' and 'cats' to 'mice' with nested `REPLACE` could end up with just 'mice' instead of 'cats' and 'mice'.