Question

在SQL Server中，这将从Customers表中插入100条记录到tmpFerdeen： -

SELECT top(100)*
INTO tmpFerdeen
FROM Customers

是否可以在UNION ALL SELECT中执行SELECT INTO： -

SELECT top(100)* 
FROM Customers
UNION All
SELECT top(100)* 
FROM CustomerEurope
UNION All
SELECT top(100)* 
FROM CustomerAsia
UNION All
SELECT top(100)* 
FROM CustomerAmericas

不太确定在哪里添加INTO子句。

Answer 1

这适用于SQL Server：

SELECT * INTO tmpFerdeen FROM (
  SELECT top 100 * 
  FROM Customers
  UNION All
  SELECT top 100 * 
  FROM CustomerEurope
  UNION All
  SELECT top 100 * 
  FROM CustomerAsia
  UNION All
  SELECT top 100 * 
  FROM CustomerAmericas
) as tmp

Answer 2

您根本不需要派生表。

只需将INTO放在第一个SELECT

之后

SELECT top(100)* 
INTO tmpFerdeen
FROM Customers
UNION All
SELECT top(100)* 
FROM CustomerEurope
UNION All
SELECT top(100)* 
FROM CustomerAsia
UNION All
SELECT top(100)* 
FROM CustomerAmericas

Answer 3

SELECT * INTO tmpFerdeen FROM 
(SELECT top(100)*  
FROM Customers 
UNION All 
SELECT top(100)*  
FROM CustomerEurope 
UNION All 
SELECT top(100)*  
FROM CustomerAsia 
UNION All 
SELECT top(100)*  
FROM CustomerAmericas) AS Blablabal

这种“Blablabal”是必要的

Answer 4

对于MS Access查询，这有效：

SELECT * INTO tmpFerdeen FROM( 
    SELECT top(100) *
    FROM Customers 
UNION All 
    SELECT top(100) *  
    FROM CustomerEurope 
UNION All 
    SELECT top(100) *  
    FROM CustomerAsia 
UNION All 
    SELECT top(100) *  
    FROM CustomerAmericas
)

这在MS Access

中无效

SELECT top(100) * 
  INTO tmpFerdeen
  FROM Customers
UNION All
  SELECT top(100) * 
  FROM CustomerEurope
UNION All
  SELECT top(100) * 
  FROM CustomerAsia
UNION All
  SELECT top(100) * 
  FROM CustomerAmericas

Answer 5

我会这样做：

SELECT top(100)* into #tmpFerdeen
FROM Customers

Insert into #tmpFerdeen
SELECT top(100)* 
FROM CustomerEurope

Insert into #tmpFerdeen
SELECT top(100)* 
FROM CustomerAsia

Insert into #tmpFerdeen
SELECT top(100)* 
FROM CustomerAmericas

Answer 6

我看到的解决方案挑战：

FROM( 
SELECT top(100) *
    FROM Customers 
UNION
    SELECT top(100) *  
    FROM CustomerEurope 
UNION 
    SELECT top(100) *  
    FROM CustomerAsia 
UNION
    SELECT top(100) *  
    FROM CustomerAmericas
)

是因为这将创建一个窗口数据集，该数据集将驻留在RAM中，而在较大的数据集上，此解决方案将产生严重的性能问题，因为它必须首先创建分区，然后将使用该分区写入临时表。

更好的解决方案是：

SELECT top(100)* into #tmpFerdeen
FROM Customers

Insert into #tmpFerdeen
SELECT top(100)* 
FROM CustomerEurope

Insert into #tmpFerdeen
SELECT top(100)* 
FROM CustomerAsia

Insert into #tmpFerdeen
SELECT top(100)* 
FROM CustomerAmericas

选择在临时表中插入，然后添加其他行。但是，这里的缺点是数据中是否有重复的行。

最佳解决方案如下：

Insert into #tmpFerdeen
SELECT top(100)* 
FROM Customers
UNION
SELECT top(100)* 
FROM CustomerEurope
UNION
SELECT top(100)* 
FROM CustomerAsia
UNION
SELECT top(100)* 
FROM CustomerAmericas

此方法应可用于需要不同行的所有目的。但是，如果您希望重复的行只需将UNION换成UNION ALL

祝你好运！

Answer 7

也许试试这个？

SELECT * INTO tmpFerdeen (
SELECT top(100)* 
FROM Customers
UNION All
SELECT top(100)* 
FROM CustomerEurope
UNION All
SELECT top(100)* 
FROM CustomerAsia
UNION All
SELECT top(100)* 
FROM CustomerAmericas)

Answer 8

尝试这样的事情：使用union的结构创建最终的对象表tmpFerdeen。

然后

INSERT INTO tmpFerdeen (
SELECT top(100)* 
FROM Customers
UNION All
SELECT top(100)* 
FROM CustomerEurope
UNION All
SELECT top(100)* 
FROM CustomerAsia
UNION All
SELECT top(100)* 
FROM CustomerAmericas
)

可以在UNION [ALL]中使用SELECT INTO子句吗？

8 个答案: