MySQL: replace into

I am having one of those nights where I appreciate Shlomi Noach's REPLACE INTO: think twice. "REPLACE INTO" is not a conditional insert or update based on if the same key exists. It's better thought of as a conditional insert OR delete then insert query. This will get you if you're trying to do a field_name=field_name in your query to preserve it's value as you would do with an update since the original field_value would be lost. I re-wrote my query to do a "INSERT ... ON DUPLICATE KEY UPDATE" instead.