Question

我们说我有2张桌子

EmpID | ProcessID | ID
2     | B         |  1
1     | A         |  2
3     | C         |  3

EmpID | ProcessID | ID
1     | F         |  1
2     | E         |  2

我想联合这两个表，并希望最终结果是

EmpID | ProcessID
2     | B
2     | E
1     | A
1     | F
3     | C

请注意，我的第一个表EmpID命令是2,1,3，它基于ID（标识）列。所以我想要的是UNION之后的最终结果也是2,1,3（按第一个表ID排序）。如果我使用UNION并按EmpID排序，我将改为

EmpID | ProcessID
1     | A
1     | F
2     | B
2     | E
3     | C

知道如何实现这个目标吗？

Answer 1

declare @t1 table (EmpID int, ProcessID varchar(10), ID int);
insert into @t1 values
(2     ,' B'         ,  1),
(1     , 'A'         ,  2),
(3     , 'C'         ,  3);

declare @t2 table (EmpID int, ProcessID varchar(10), ID int);
insert into @t2 values
(1     , 'F'         ,  1),
(2     , 'E'         ,  2);

with cte2 as
(
select  t2.EmpID, t2.ProcessID, t1.ID, 2 as nr
from @t1 t1 join @t2 t2
        on t1.EmpID = t2.EmpID
),

cte1 as
(
select  *, 1 as nr
from @t1
)

select EmpID, ProcessID
from
    (
    select *
    from cte1
    union all
    select *
    from cte2
    )t
order by id, nr;

Answer 2

如果您只需要两个第一列并删除ID列，但仍然能够按其排序，则可以这样做：

SELECT
    EmpID
   ,ProcessID
FROM
(
    SELECT
       *
    FROM
       #tmp1 AS T
    UNION
    SELECT
       *
    FROM
       #tmp2 AS T
) AS A
ORDER BY
    id ASC

编辑：我注意到您的ID列在第一个表上升序排序并在辅助表上降序 - 如果总是如此，您可以这样：

SELECT
    EmpID
   ,ProcessID
FROM
(
    SELECT
       EmpID
      ,ProcessID
      ,row_number() OVER (ORDER BY id asc) AS rw
    FROM
       #tmp1 AS T
    UNION
    SELECT
       EmpID
      ,ProcessID
      ,row_number() OVER (ORDER BY id desc) AS rw
    FROM
       #tmp2 AS T
) AS A
ORDER BY
    rw ASC

Answer 3

试试这个脚本：

false

输出：

if (isset($_SESSION["id"])) {

UNION但保留第一个表排序顺序

3 个答案: