Select from MySQL by connecting two columns together?

Question

To give you an idea of what I'm trying to achieve here, I've set up a very simple mail system where users can "Star" incoming or outgoing mail (To read later or save, etc...). The system is VERY simple and works with a similar table design to below, please note that I've removed some columns which aren't relevant here:

Random Digit
User ID of Recipient
User ID of Sender
Message
If recipient has starred message (0 for no, 1 for yes)
If sender has starred the message (0 for no, 1 for yes)

mail_id  |  recip_account  |  sender_account  |  message  |  recip_starred  |  sender_starred 
   1            5                 10             Hello          0                  1
   2            10                 5            A Reply         0                  1
   3            10                20             Test           1                  0
   4            15                20             Message        1                  1

From the examples above, if we are getting starred messages for user ID 10 , the query would show Message ID's 1, 3 . As you can probably work out - I can retrieve starred messages easily if viewing only Received or Sent messages separately. Although, the issue here is I would like to show all "Starred" messages in a single folder for each user, and obviously that requires working out which user has starred the message, or by connecting the recip_account & recip_starred OR sender_account & sender_starred and reference that against a user ID?

Can anybody help me out here, the currently way I am retrieving results is as follows:

$sql2 = "SELECT * FROM `ap_mail_system` WHERE `recip_account` = '$user_id' OR `sender_account` = '$user_id' ORDER BY `sent_date` DESC LIMIT 0, 12"; 

Answer 1

You just need a bit of boolean logic in your WHERE clause. Try:

SELECT * FROM `ap_mail_system` WHERE (`recip_account` = '$user_id' AND `recip_starred` = 1) OR (`sender_account` = '$user_id' AND `sender_starred` = 1) ORDER BY `sent_date` DESC LIMIT 0, 12