表的并列

Question

我有表A：

Id
________
-1
-2
-3

我有表B：

Id
_________
110
111
112

如何从表A和表B中获取包含列的结果表的最佳实践：

IdA | IdB
__________
-1  | 110
-2  | 111
-3  | 112

Answer 1

一种方法是使用几个CTE和ROW_NUMBER。我假定，值应分别以降序和升序连接。这意味着，如果要分别添加值-4和109，则-1和109将被联接，而不是-1和110 （以及-4和112）。

WITH A AS(
    SELECT Id,
           ROW_NUMBER() OVER (ORDER BY Id DESC) AS I
    FROM TableA),
B AS(
    SELECT ID
           ROW_NUMBER() OVER (ORDER BY ID ASC) AS I
    FROM TableB)
SELECT A.ID AS IdA,
       B.ID AS IdB
FROM A
     JOIN B ON A.I = B.I;

Answer 2

这是一个很好的解决方案。

SELECT AA.Id AS IdA ,BB.Id As IdB  FROM 
 (SELECT Id, ROW_NUMBER() OVER(ORDER BY (SELECT 100)) As row_num FROM A ) AS AA
 INNER JOIN 
 (SELECT Id, ROW_NUMBER() OVER(ORDER BY (SELECT 100)) AS row_num  FROM B)  AS BB
 ON AA.row_num = BB.row_num 

Answer 3

使用数据集中的row_number()（我假设两个表列的项目数均相同）

with cte as
(select id,row_number()over(order by (select null)) rn
 from tableA
),cte1 as
( 
select id,row_number()over(order by (select null)) rn from tableB
) select cte.id,cte1.id cte join ct1 on ct1.rn=cte.rn