处理字符串_1_生成自增值

                           生成自增值

需求描述

需求：通过SQL生成一个1到1000条记录.

解决方法:通过CTE的递归来实现该需求.

注: 数据库数据集SQL脚本详见如下链接地址

​​员工表结构和数据初始化SQL脚本​​

SQL代码

-- SQL Server:
DECLARE @start INT, @end INT
SELECT @start=1, @end=1000
;WITH NumberSequence( Number ) AS
(
    SELECT @start AS Num
        UNION ALL
    SELECT Number + 1
        FROM NumberSequence
        WHERE Number < @end
) 
SELECT * FROM NumberSequence OPTION (MaxRecursion 1000)

执行结果

--Oracle:
WITH t(num) AS (
  SELECT 1 FROM DUAL
  UNION ALL
  SELECT t.num+1
  FROM t WHERE t.num<100
  )
SELECT * FROM t;

--Mysql(8.0及以上版本):
WITH RECURSIVE cte (num) AS
(
  SELECT 1
  UNION ALL
  SELECT num + 1 FROM cte WHERE num < 100
)
SELECT * FROM cte;