返回一个标量值比返回一个结果集更高效，原因是结果集带有更多的辅助方法，这使得它很重从而增加了延迟在对象从 sql 到 C# 代码/例程的传输中.

Returning a scalar value is more efficient than a result set, the reason is result set carries lot more helper methods along with it, which makes it heavy thus increasing latency in transmission of the object from sql to C# code/routine.

在您的方法 3 中:您使用了一个变量来返回该值，这比发送一个 out 参数更好，因为在这里您至少在一个路由中减少了一个对象的遍历(即，在调用存储过程时).

In your method 3: You have used a variable to return the value this is more better than sending an out parameter since here you are cutting down on traverse of an object atleast in one route ( i.e., when invoking the stored procedure).

结果集比输出参数更灵活，因为它可以返回多行(显然)，所以如果您需要结果集，那么无论如何它是唯一的选择.

A result set is more flexible than an output parameter because it can return multiple rows (obviously), so if you need a result set then it's the only choice anyway.

按照方法 3、方法 2、方法 1 的性能对查询进行排序.

To order the queries based on performance that goes as Method 3, Method 2 Method 1.

希望这有助于理解这个概念.

Hope this is helpful in understanding the concept.