Question

是否可以在不使用循环函数的情况下创建行？

＆＃xA;＆＃xA;

SQL

＆＃xA;＆＃xA;

  CREATE TABLE #tempTable（id int）＆＃xA; DECLARE @i int = 0＆＃xA; DECLARE @numrows int = 5＆＃xA; WHILE @ i＆lt; @ numrows＆＃xA; BEGIN＆＃xA; INSERT INTO #tempTable VALUES（@i） ＆＃xA; SET @i = @ i + 1＆＃xA; END＆＃xA; SELECT * FROM＃tempTable＆＃xA;

＆＃xA;＆＃xA;

我可以获得相同的结果没有循环。我正在使用SQL Server 2014

＆＃xA;

Answer 1

请尝试从此处https://sqlperformance.com/2013/01/t-sql-queries/generate-a-set-1

获取此信息

SELECT TOP (5) n = CONVERT(INT, ROW_NUMBER() OVER (ORDER BY s1.[object_id]))
INTO #tempTable
FROM sys.all_objects AS s1 CROSS JOIN sys.all_objects AS s2

SELECT *
FROM #tempTable

Answer 2

你也可以使用numbers表

INSERT INTO #tempTable 
select number from numbers where number<=5

Answer 3

您可以使用Tally table的概念，可以像下面这样创建

DECLARE @numrows int = 5

select 
 top (select @numrows)
 row_number() over( order by (select 1)) id
from
sys.objects s1 cross join
sys.objects s2

请注意，我们在查询SELECT

中没有使用s1或s1中的任何内容

的 See working demo

Answer 4

另一个不涉及从任意表读取数据的选项是使用＆＃34;数字函数＆＃34;生成人工行，可以进一步转变为喂养其他表。这样的事情会做：

WITH
L0   AS(SELECT 1 AS c UNION ALL SELECT 1),
L1   AS(SELECT 1 AS c FROM L0 AS A, L0 AS B),
L2   AS(SELECT 1 AS c FROM L1 AS A, L1 AS B),
L3   AS(SELECT 1 AS c FROM L2 AS A, L2 AS B),
L4   AS(SELECT 1 AS c FROM L3 AS A, L3 AS B),
L5   AS(SELECT 1 AS c FROM L4 AS A, L4 AS B),
Nums AS(SELECT ROW_NUMBER() OVER(ORDER BY c) AS n FROM L5)
INSERT INTO #tempTable (id)
SELECT n FROM Nums WHERE n <= @numrows

最初取自http://www.sommarskog.se/arrays-in-sql-2005.html#fn_nums

在不循环SQL的情况下创建行

4 个答案: