How do I insert a record into a MySQL Database only if an existing record doesn't exist?
Posted on 2009-12-21
I have MySQL table like the following :
Domain -=- A domain name
Date -=- The date the domain was added to the database
Rank -=- A metric that we calculate for the domain
None of the values are unique. For example you could have the domain name "example.com" with a different Rank value for the past 7 days so there'd be 7 entries in the database all with different dates.
We are calculating a new "Rank" value in PHP but we only want to add it to the database if it's different to the last value in the database. So we need to look at the date column for the specified domain and only add a record if the Rank is different from the currently calculated Rank.
I'm not sure if I should be doing this with multiple queries or if there's a way to do this with one mySQL query?