将函数从 SQL 服务器转换为 PostgreSQL

Question

有人可以将此功能从 SQL 服务器转换为 PostgreSQL 吗？

此函数获取开始日期和结束日期并创建日期范围并生成输出。

CREATE FUNCTION [dbo].[DateRange]
(     
      @Increment              CHAR(1),
      @StartDate              DATETIME,
      @EndDate                DATETIME
)
RETURNS  
@SelectedRange    TABLE 
(IndividualDate DATETIME)
AS 
BEGIN
      ;WITH cteRange (DateRange) AS (
            SELECT @StartDate
            UNION ALL
            SELECT 
                  CASE
                        WHEN @Increment = 'd' THEN DATEADD(dd, 1, DateRange)
                        WHEN @Increment = 'w' THEN DATEADD(ww, 1, DateRange)
                        WHEN @Increment = 'm' THEN DATEADD(mm, 1, DateRange)
                  END
            FROM cteRange
            WHERE DateRange <= 
                  CASE
                        WHEN @Increment = 'd' THEN DATEADD(dd, -1, @EndDate)
                        WHEN @Increment = 'w' THEN DATEADD(ww, -1, @EndDate)
                        WHEN @Increment = 'm' THEN DATEADD(mm, -1, @EndDate)
                  END)

      INSERT INTO @SelectedRange (IndividualDate)
      SELECT DateRange
      FROM cteRange
      OPTION (MAXRECURSION 3660);
      RETURN
END
GO

Answer 1

不需要自己写函数，这个已经内置了：

select * 
from generate_series(date '2016-01-01', date '2016-09-01', interval '2' day);

手册中的详细信息：https://www.postgresql.org/docs/current/static/functions-srf.html

将函数从 SQL 服务器转换为 PostgreSQL

Convert Function from SQL Server to PostgreSQL

sql

postgresql

stored-functions