Question

无法正确说出问题，因此无法搜索我想要的内容。我需要的只是一个带有一列说guid的虚拟表，我将它用于其他目的。没有实际编写相同的insert .. newID() n次，想知道是否有一个优雅的解决方案。

类似的问题是如何使用带有1-n数字的int列填充空白表。

Row1: 1
Row2: 2
.......
Row100:100

Answer 1

你可以递归地做。

对于数字，f.ex。：

WITH r AS (
    SELECT 1 AS n
    UNION ALL
    SELECT n+1 FROM r WHERE n+1<=100
)
SELECT * FROM r

Answer 2

我建议您使用已知超过100行的任何对象，而不是递归CTE。

--INSERT dbo.newtable(ID, GUID)
SELECT TOP (100) ROW_NUMBER() OVER (ORDER BY [object_id]), NEWID()
  FROM sys.all_columns ORDER BY [object_id];

有很多其他想法，请参阅本系列文章：

Answer 3

单向;

;with guids( i, guid ) as
(
    select 1 as i, newid() 
        union all
    select i + 1, newid() 
        from guids
        where i < 100
)

select guid from guids option (maxrecursion 100)

Answer 4

这种方法非常快。如果你需要从零开始生成一个数字表，它可能是“最好的”可用方法。

WITH
  t0(i) AS (SELECT 0 UNION ALL SELECT 0),
  t1(i) AS (SELECT 0 FROM t0 a, t0 b),
  t2(i) AS (SELECT 0 FROM t1 a, t1 b),
  t3(i) AS (SELECT 0 FROM t2 a, t2 b),
  n(i) AS (SELECT ROW_NUMBER() OVER(ORDER BY (SELECT 0)) FROM t3)
SELECT i FROM n WHERE i BETWEEN 1 AND 100

Answer 5

只需添加未列出的内容即可

获取10行的快速方法：

SELECT ROW_NUMBER() OVER(
        ORDER BY N1.N) 
        , LOWER(NEWID())
    FROM   (VALUES(1), (1), (1), (1), (1), (1), (1), (1), (1), (1)) AS N1(N)          -- 10

如果您希望它基于变量：

DECLARE  @N int = 10;
WITH Numbers(number)
     AS (SELECT ROW_NUMBER() OVER(
                ORDER BY N1.N)
         FROM   (VALUES(1), (1), (1), (1), (1), (1), (1), (1), (1), (1)) AS N1(N)          -- 10
                CROSS JOIN(VALUES(1), (1), (1), (1), (1), (1), (1), (1), (1), (1)) AS N2(N)-- 100  
                --CROSS JOIN (VALUES (1),(1),(1),(1),(1),(1),(1),(1),(1),(1)) AS N3 (N)   -- 1,000
                --CROSS JOIN (VALUES (1),(1),(1),(1),(1),(1),(1),(1),(1),(1)) AS N4 (N)   -- 10,000
                --CROSS JOIN (VALUES (1),(1),(1),(1),(1),(1),(1),(1),(1),(1)) AS N5 (N) -- 100,000
                -- Etc....
)
     SELECT *
          , LOWER(NEWID())
     FROM   Numbers
     WHERE  number <= @N;

在表中生成固定数量的行

5 个答案: