Query for lowest price for product in same row
Of course your data is denormalized, otherwise it would be a simple MIN(price) :-)

If you got luck your DBMS supports a LEAST function:

LEAST(price_one,price_two,price_three,price_four,price_five),


A huge CASE is supported in every DBMS:

CASE
  WHEN price_one &lt;= price_two
   AND price_one &lt;= price_three
   AND price_one &lt;= price_four
   AND price_one &lt;= price_five
  THEN price_one

  WHEN price_two &lt;= price_three
   AND price_two &lt;= price_four
   AND price_two &lt;= price_five
  THEN price_two

  WHEN price_three &lt;= price_four
   AND price_three &lt;= price_five
  THEN price_three

  WHEN price_four &lt;= price_five
  THEN price_four

  ELSE price_five
END


Hopefully there are no NULLs...