Question

I have a column called submit_timestamp which holds a UNIX_TIMESTAMP(), what I want to do now is do a SELECT query and within the WHERE clause ensure the submit_timestamp equals or is within X number of days.

(Demonstration purposes only):

SELECT id
FROM   submissions
WHERE  submit_timestamp = 'EQUALS OR IS WITHIN X NUMBER OF DAYS FROM submit_timestamp'
       AND id = 2  

All help appreciated.

Thanks.

Answer 1

Compute the two times you want to compare to in your application before you construct the query. All programming languages will have a function to give you the current timestamp (i.e. time() in PHP). To get “X days from now”, add 60*60*24*X seconds to the timestamp.

SELECT id
FROM   submissions
WHERE  submit_timestamp >= $THE_CURRENT_TIMESTAMP
       AND submit_timestamp <= ($THE_CURRENT_TIMESTAMP + 60*60*24*X)
       AND id = 2  

Now you’re just comparing integers. Unlike Johan’s solution, MySQL will be able to use an index on the column for the comparisons.