将两个Linq查询的结果合并到单个变量中? [英] Combining The Results Of Two Linq Queries Into A Single Var?

问题描述

我有两个不同的数据库，其中包含两个设计完全相同的表.如何最有效地合并这两个查询的结果?我知道我可以将每个结果放入字典或数组等中，但是我想有一种更简单的方法可以做到这一点.

I have two different databases that contain two tables with the exact same design. How do I combine the results from these two queries most efficiently? I know I can put the results of each into a dictionary or array or whatever, but I would like to think that there is a simpler way to do this.

var db1 = //A database object connected to database1
var db2 = //A database object connected to database2

var result1 = db1.table.where(a=>a.value>0);
var result2 = db2.table.where(a=>a.value>0);

var resultSum = result1+result2; //???

谢谢！

附录:Concat或Union，对于这种特殊情况哪个更好，为什么?谢谢！

Addendum: Concat or Union, which is better for this particular case and why? Thanks!

推荐答案

您只能合并相同类型的枚举，可以将它们都投影到相同的类中，然后将它们连接起来:

You can only combine enumerations of the same type, you could project both to a common class and then concatenate them:

var result1 = db1.table.Where(a=>a.value>0).Select( x=> new Foo() { /*set props*/ });
var result2 = db2.table.Where(a=>a.value>0).Select( x=> new Foo() { /*set props*/ });

var resultSum = result1.Concat(result2);

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