SQL 中的最后一行

Question

我有这样的查询

select  top 1* from table1 where organizationID= 79 order by D_Index desc
select  top 1* from table1 where organizationID= 87 order by D_Index desc
select  top 1* from table1 where organizationID= 19 order by D_Index desc

我在这里尝试获取 table 1 中针对 organizationID 的最后数据 .. 表示 79,87 和 19 的最后数据，并尝试与 union all 结合，但这显示错误

select  top 1* from table1 where organizationID= 79 order by D_Index desc union all 
select  top 1* from table1 where organizationID= 87 order by D_Index desc union all 
select  top 1* from table1 where organizationID= 19 order by D_Index desc

如果我写这个

  select  top 1* from table1 where organizationID= 79  union all 
    select  top 1* from table1 where organizationID= 87  union all 
    select  top 1* from table1 where organizationID= 19  
order by D_Index desc

然后这显示第 1 行 79 和 87 以及最后一行 19 但我想要最后一行反对 79,87 和 19

有什么帮助吗？

Answer 1

;WITH CTE as
(
  SELECT
    *,
    row_number() over (partition by organizationID order by D_Index desc) rn
  FROM
    table1
  WHERE organizationID in (19,79,87)
)
SELECT *
FROM CTE
WHERE rn = 1

没有 CTE（按要求）

SELECT *
FROM 
  (
    SELECT
      *,
      row_number() over (partition by organizationID order by D_Index desc) rn
    FROM
      table1
    WHERE organizationID in (19,79,87)
  ) x
WHERE rn = 1

Answer 2

@t-clausen.dk 的回答是去这里的方法，但这里有一种方法可以使您当前的方法起作用：

SELECT * FROM
    (SELECT TOP 1 * FROM table1 WHERE organizationID = 79 ORDER BY D_Index DESC) t1
UNION ALL
SELECT * FROM
    (SELECT TOP 1 * FROM table1 WHERE organizationID = 87 ORDER BY D_Index DESC) t2
UNION ALL
SELECT * FROM
    (SELECT TOP 1 * FROM table1 WHERE organizationID = 19 ORDER BY D_Index DESC) t3;

发生错误是因为 ORDER BY 不能出现在联合查询（或任何查询）的中间。但是，如果我们将您的查询包装为子查询，那么我们可以对它们使用 ORDER BY）。

同样，使用 ROW_NUMBER 是前往此处的方法，但如果您需要使用此类语法，只要编写正确，是可能的。

SQL 中的最后一行

Last row in SQL

sql

sql-server

union-all