使用 2 个以上表的联合覆盖按字母顺序排列的默

问题描述

非常简单的问题...我有 4 个表，它们是 UNION 结合在一起的，如下所示:

Really quick question... I have 4 tables that are UNION-ed together like so:

SELECT * FROM table1  
UNION
SELECT * FROM table2  
UNION
SELECT * FROM table3  
UNION
SELECT * FROM table4

不指定 ORDER BY，查询按字母升序排列第一列(在我的例子中恰好是 varchar 类型).我也不想要 ORDER BY [Column1] DESC.

Without specifying an ORDER BY, the query orders by the first column in ascending alphabetical order (which in my case happens to be a varchar type). I don't want ORDER BY [Column1] DESC either.

我只是想按照与表本身UNION-ed 相同的顺序对结果进行排序.1、2、3、4.

I simply want to order the results in the same order as the tables themselves are UNION-ed. 1, 2, 3, 4.

有没有简单的方法可以做到这一点?

Is there a simply way to do this?

谢谢！！

推荐答案

一种方式

SELECT *,1 as SortOrder FROM table1  
UNION
SELECT *,2 FROM table2  
UNION
SELECT *,3 FROM table3  
UNION
SELECT *,4 FROM table4
order by SortOrder 

发生的事情是你使用了 UNION，然后 sql server 使结果集不同，为了做到这一点，它需要对表进行排序

what happens is that you are using UNION, sql server then makes the result set distinct, in order to do that it needs to sort the tables

UNION ALL 有什么不同吗?

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