How to check if a value already exists to avoid duplicates?

Question

I\'ve got a table of URLs and I don\'t want any duplicate URLs. How do I check to see if a given URL is already in the table using PHP/MySQL?

Answer 1

If you want to insert urls into the table, but only those that don't exist already you can add a UNIQUE contraint on the column and in your INSERT query add IGNORE so that you don't get an error.

Example: INSERT IGNORE INTO urls SET url = 'url-to-insert'