其他答案都很好，但如果你不得不担心有NULL值，你可能会想要这个变体:

SELECT o.OrderId, 
   CASE WHEN ISNULL(o.NegotiatedPrice, o.SuggestedPrice) > ISNULL(o.SuggestedPrice, o.NegotiatedPrice)
        THEN ISNULL(o.NegotiatedPrice, o.SuggestedPrice)
        ELSE ISNULL(o.SuggestedPrice, o.NegotiatedPrice)
   END
FROM Order o

如果你使用的是SQL Server 2008(或更高版本)，那么这是更好的解决方案:

SELECT o.OrderId,
       (SELECT MAX(Price)
        FROM (VALUES (o.NegotiatedPrice),(o.SuggestedPrice)) AS AllPrices(Price))
FROM Order o

所有的信用和投票都应该去Sven对一个相关问题的答案，“多列的SQL MAX ?” 我说这是“最佳答案”，因为:

It doesn't require complicating your code with UNION's, PIVOT's, UNPIVOT's, UDF's, and crazy-long CASE statments. It isn't plagued with the problem of handling nulls, it handles them just fine. It's easy to swap out the "MAX" with "MIN", "AVG", or "SUM". You can use any aggregate function to find the aggregate over many different columns. You're not limited to the names I used (i.e. "AllPrices" and "Price"). You can pick your own names to make it easier to read and understand for the next guy. You can find multiple aggregates using SQL Server 2008's derived_tables like so: SELECT MAX(a), MAX(b) FROM (VALUES (1, 2), (3, 4), (5, 6), (7, 8), (9, 10) ) AS MyTable(a, b)

可以在一行中完成:

-- the following expression calculates ==> max(@val1, @val2)
SELECT 0.5 * ((@val1 + @val2) + ABS(@val1 - @val2)) 

编辑:如果处理的是非常大的数字，则必须将值变量转换为bigint，以避免整数溢出。

SELECT o.OrderID
CASE WHEN o.NegotiatedPrice > o.SuggestedPrice THEN
 o.NegotiatedPrice
ELSE
 o.SuggestedPrice
END AS Price

 -- Simple way without "functions" or "IF" or "CASE"
 -- Query to select maximum value
 SELECT o.OrderId
  ,(SELECT MAX(v)
   FROM (VALUES (o.NegotiatedPrice), (o.SuggestedPrice)) AS value(v)) AS MaxValue
  FROM Order o;

对于SQL Server 2012:

SELECT 
    o.OrderId, 
    IIF( o.NegotiatedPrice >= o.SuggestedPrice,
         o.NegotiatedPrice, 
         ISNULL(o.SuggestedPrice, o.NegiatedPrice) 
    )
FROM 
    Order o