How do I compare 2 tables looking for missing items

[phoshaqu]

I have two tables one that contains a huge list of items and another that trading for those items.Here are examples tables:The main table\[code\]| ID | TITLE | STATUS | TRADE |-------------------------------| 1 | test1 | 1 | 1 || 2 | test2 | 1 | 1 || 3 | test3 | 1 | 0 || 4 | test4 | 0 | 1 |\[/code\]The trade table\[code\]| ID | TRADER | ITEM | URL |------------------------------------------------------| 1 | 2 | 1 | HTTP://www.test.com/itemOne || 2 | 5 | 3 | HTTP://www.test.com/itemThree || 3 | 5 | 4 | HTTP://www.test.com/itemFour |\[/code\]Say I want to have a list of all the items that are not being traded by trader 5 and have a status of 1. So when trader 5 comes to the site they will be able to select the remaining items to trade.Here is what I have tried:\[code\]$sql = "SELECT m.id, m.title FROM main AS m, trade AS t WHERE m.trade >= 1 && m.status = 1 && t.trader <>". mysql_real_escape_string($traderID);\[/code\]This code just doesn't work. Any ideas on this?