SQL服务器是否等同于Oracle ?

I've been looking for a good equivalent to the Oracle LEAST function.

我一直在寻找一个与Oracle最小功能相当的东西。

I'm hoping to implement a user defined function that does about 10 fairly complex calculations, and takes the minimum value from each of those calculations.

我希望实现一个用户定义的函数，它执行大约10个相当复杂的计算，并从每个计算中取最小值。

What I would do in Oracle is:

我在Oracle中会做的是:

SELECT LEAST
(
select expression1 from dual,
select expression2 from dual,
select expression3 from dual
) from dual

See http://www.techonthenet.com/oracle/functions/least.php for more on Oracle LEAST.

有关Oracle的更多信息，请参见http://www.techonthenet.com/oracle/functions/least.php。

If expression1 returned 10, expression2 return 5, and expression3 reeturned 30, the whole expression would return 5.

如果表情返回10，表情返回5，表情返回30，整个表情将返回5。

Because this may be about 10-20 calculations, the CASE WHEN syntax is going to get unwieldy fast.

因为这可能需要10-20次计算，所以语法会很快变得难以处理。

Although the code will be more readable if we break it up more, I thought it would be more efficient to do it within one database query. Let me know I'm incorrect on that point, please!

虽然如果我们把代码分解得更多一些，代码会更容易阅读，但是我认为在一个数据库查询中做它会更有效率。请让我知道在那一点上我错了!

I.e., is a stored procedure with 20 simple queries significantly slower than a stored procedure with one query that references a lot of tables all in one query.

即。，是一个包含20个简单查询的存储过程，比一个包含一个查询的存储过程慢得多，该查询在一个查询中引用了许多表。

2 个解决方案

#1

mayby this query could help:

mayby这个查询可以帮助:

 SELECT  min(c1)  
 from ( 
      select expression1 as c1  
      union all
      select expression2 as c1 
      union all 
      select expression3 as c1
 )

#2

-1

The function Least() is applied horizontally in Oracle (on a row level), while Min() is applied vertically over a column. The example in the question required Min().

函数Least()在Oracle中水平应用(在行级别上)，而Min()在列上垂直应用。问题中的示例需要Min()。

#1