Question

我有一个这样的SQL语句：

编辑：

SELECT 
    location as Location 
FROM
    Table1 
WHERE 
    OnsiteOffshore = 'Offshore' AND Acc_Code = 'ABC' 

UNION 

SELECT 
    Country 
FROM 
    Table1 
WHERE
    OnsiteOffshore = 'Onsite' AND Acc_Code = 'ABC'

此SQL查询提供以下结果：

Chennai
Bangalore
USA
NewZealand

但由于某些要求，我需要输出如下：

Chennai
Chennai
Chennai
Chennai
Bangalore
Bangalore
Bangalore
Bangalore
USA
USA
USA
USA
NewZealand
NewZealand
NewZealand
NewZealand

意思是说每个位置需要输出4次。

请帮忙解决问题。

Answer 1

SELECT Location 
FROM Table1
  CROSS JOIN
    ( VALUES (1),(2),(3),(4)
    ) AS four(dummy)

如果4不是常量但是（因为@xQbert注意/询问）是表的行数，您可以使用：

SELECT a.Location 
FROM Table1 AS a
  CROSS JOIN
     Table1 AS b

如果您没有Table1但任何（但是很复杂的）查询，您可以将其用于4份副本：

SELECT Location 
FROM (
       SELECT Location       --- complex query here
       ...                   --- inside parenthesis
     UNION 
       SELECT Country
       ...
     ) AS Table1
  CROSS JOIN
    ( VALUES (1),(2),(3),(4)
    ) AS four(dummy)

或n份副本：

WITH cte AS
  ( SELECT Location       --- complex query here
    ...                   --- inside parenthesis
    UNION 
    SELECT Country
    ...
  )
SELECT a.Location 
FROM cte AS a
  CROSS JOIN
     cte AS b

Answer 2

在任何RDBMS中最简单且（可能）完全接受; - ）：

select location from (
    Select Location From Table1 union all
    Select Location From Table1 union all
    Select Location From Table1 union all
    Select Location From Table1
) t
order by location

使用CTE (Common Table Expressions)更好的方式：

;with cte (id) as (
    select 1 union all
    select id + 1 from cte where id < 4
)
select location from Table1
cross join cte

Answer 3

您可以为此创建一个包装程序...其中，您首先为Select Location From Table1创建游标，而不是循环浏览此游标并以任何方式提取数据。

您可以选择使用某些前端技术来执行此操作。对于前端语言，即Java，C ++，.NET或任何其他流行语言，这不是一项艰巨的任务。

Answer 4

仅在Table1至少有4条记录

时才有效

SELECT Location
FROM Table1 a, (select top 4 id from Table1) b 
order by a.Location

Answer 5

DECLARE @counter int
DECLARE @max int = 4

CREATE TABLE #myTable (
    Name nvarchar(50)
)

SET @counter = 0

WHILE @counter < @max

BEGIN
    INSERT INTO #myTable SELECT cityname FROM citytable

    SET @counter = @counter + 1
END


SELECT name FROM #myTable ORDER BY name

DROP TABLE #myTable

Answer 6

select t1.location 
from table1 t1, table1 t2

应返回n的n个位置。因此，如果地点包含10个条目，其中一个是美国，美国将列出10次。这会根据输入的位置数量进行缩放。

或更现代的语法：

Select t1.location
from table1 t1
Cross join table1 t2

注意缺少ON条款;那是因为我们想要自我加入的笛卡尔积。

- 编辑反映已更改的SQL

Select A.Location 
FROM (
  Select  location as Location 
  from Table1 where OnsiteOffshore = 'Offshore' and Acc_Code = 'ABC' 
  UNION 
  Select  Country 
  from Table1 where OnsiteOffshore = 'Onsite' and Acc_Code = 'ABC') A
CROSS JOIN (
  Select  location as Location 
  from Table1 where OnsiteOffshore = 'Offshore' and Acc_Code = 'ABC' 
  UNION 
  Select  Country 
  from Table1 where OnsiteOffshore = 'Onsite' and Acc_Code = 'ABC') B

Answer 7

8 - ）

Select Location From Table1 UNION ALL
Select Location From Table1 UNION ALL
Select Location From Table1 UNION ALL
Select Location From Table1 
ORDER BY 1

从表中多次选择记录

7 个答案: