Question

What does <> mean in SQL language: Sample code is as follows

SELECT ordid,
       prodid,
       qty
FROM   item
WHERE  prodid IN (SELECT prodid
                  FROM   item
                  WHERE  ordid = 605)
       AND qty IN (SELECT qty
                   FROM   item
                   WHERE  ordid = 605)
       AND ordid <> 605;  

Answer 1

It means ‘not equal to’. So you’re filtering out records where ordid is 605. Overall you’re looking for any records which have the same prodid and qty values as those assigned to ordid 605, but which are for a different order.