带有列标识符的Sql视图

Question

我正在创建一个包含三个表的联合的选择查询....就像这样

select a as A,b as B c as C where c = x union
select b as A,d as B e as C where e = y and d = a union
select f as A,g as B,h as C

查询结果如下:

A   B   C
===========
1   abc ...
55  def ...
1   sas ...

所以我想要一个计算行数的列,只是为了防止重复标识符.像这样的东西

Row  A   B   C
================
1    1   abc ...
2    55  def ...
3    1   sas ...

....

我的问题是它是如何做到的？

Answer 1

您可以像这样使用ROW_NUMBER():

SELECT ROW_NUMBER() OVER (ORDER BY A,B,C) AS RowNo, *
FROM
(
select a as A,b as B c as C where c = x 
union
select b as A,d as B e as C where e = y and d = a 
union
select f as A,g as B,h as C
) x