Question

我正在使用三个表的联合创建一个选择查询.... 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 ...

所以我希望有一个列数来计算行数，只是为了防止重复标识符。这样的事情

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

...

我的问题是如何做到这一点？

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

Answer 2

CREATE VIEW dbo.vname
AS
    SELECT [Row] = ROW_NUMBER() OVER (ORDER BY A), A, B, C FROM
    ( <UNION query here> ) AS x;

将ORDER BY A替换为您希望应用的任何顺序。请注意，您需要在针对dbo.viewname的外部查询上使用ORDER BY，以保证Row将按此顺序出现。

Answer 3

您可以使用公用表表达式来实现此目的：

WITH unionTable
AS
(
    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
)
SELECT ROW_NUMBER() OVER (ORDER BY A) AS RowNumber, * 
FROM unionTable

带有列标识符的Sql视图

3 个答案: