MySql Query - INSERT INTO command but only without duplicates
I have this workable query which is inserting proper data into 'selections' table according to some conditions:

    INSERT INTO selections (auctionid, selections.order)
    VALUES 
    ((SELECT id FROM auctions, game WHERE auctions.BetfairMark = game.BetfairMarketID), 1,
    ((SELECT id FROM auctions, game WHERE auctions.BetfairMark = game.BetfairMarketID), 2,
    ((SELECT id FROM auctions, game WHERE auctions.BetfairMark = game.BetfairMarketID), 3

but my problem is how to improve this query to prevent getting same duplicates in table when running this query?

Selections table have 3 columns: id, auctionid, order  where id is autoincrement number generated for each new record. 

So auctionid and order shouldn't be the same values in record. 
MySql Query - INSERT INTO command but only without duplicates
===

I have this workable query which is inserting proper data into 'selections' table according to some conditions:

    INSERT INTO selections (auctionid, selections.order)
    VALUES 
    ((SELECT id FROM auctions, game WHERE auctions.BetfairMark = game.BetfairMarketID), 1,
    ((SELECT id FROM auctions, game WHERE auctions.BetfairMark = game.BetfairMarketID), 2,
    ((SELECT id FROM auctions, game WHERE auctions.BetfairMark = game.BetfairMarketID), 3

but my problem is how to improve this query to prevent getting same duplicates in table when running this query?

Selections table have 3 columns: id, auctionid, order  where id is autoincrement number generated for each new record. 

So auctionid and order shouldn't be the same values in record. 